Handheld blur evaluating apparatus, handheld blur evaluating method, manufacturing method of imaging unit, and storage medium

ABSTRACT

A handheld blur evaluating apparatus is configured to evaluate a handheld blur of an imaging unit. The handheld blur evaluating apparatus includes an excitation unit configured to excite the imaging unit configured to image an object, a detector configured to detect disturbance in a change amount in measurement data of an image imaged by changing an imaging condition relating to exposure time or luminance, and a driving state indicating that the excitation unit is in a stationary state or in an excitation state, and a corrector configured to correct the disturbance.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of International Patent ApplicationNo. PCT/JP2021/047057, filed on Dec. 20, 2021, which claims the benefitof Japanese Patent Application No. 2021-008831, filed on Jan. 22, 2021,both of which are hereby incorporated by reference herein in theirentirety.

BACKGROUND Technical Field

One of the aspects of the embodiments relates to a handheld blur (blur)evaluating apparatus configured to evaluate the handheld blur in animaging unit.

Description of Related Art

PCT International Publication No. WO 2013/076964 discloses a measuringapparatus for measuring an effect of an image stabilizing function of atarget camera (imaging unit) by imaging a chart by the target camerathat is fixed to a (vibration) excitation table of a (vibration)excitation apparatus, and by analyzing the resultant image using acomputer.

However, the measuring apparatus disclosed in WO 2013/076964 cannotevaluate the handheld blur in the imaging unit with high accuracy.

SUMMARY

A handheld blur evaluating apparatus according to one aspect of theembodiment is configured to evaluate a handheld blur of an imaging unit.The handheld blur evaluating apparatus includes an excitation unitconfigured to excite the imaging unit configured to image an object, adetector configured to detect disturbance in a change amount inmeasurement data of an image imaged by changing an imaging conditionrelating to exposure time or luminance, and a driving state indicatingthat the excitation unit is in a stationary state or in an excitationstate, and a corrector configured to correct the disturbance.

A handheld blur evaluating method corresponding to each of the handheldblur evaluating apparatuses also constitutes another aspect of thedisclosure. A non-transitory computer-readable storage medium storing aprogram that causes a computer to execute the above handheld blurevaluating method also constitutes another aspect of the disclosure.

Further features of the disclosure will become apparent from thefollowing description of embodiments with reference to the attacheddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A, 1B, and 1C schematically illustrate a handheld blur evaluatingapparatus according to a first embodiment.

FIG. 2 illustrates a locus image in the first embodiment.

FIG. 3 is an extraction graph of a locus of a center of gravity of apoint image in the first embodiment.

FIG. 4 is a perspective view of the handheld blur evaluating apparatusaccording to the first embodiment.

FIG. 5 illustrates a locus image in the first embodiment.

FIG. 6 is an extraction graph of the locus of the center of gravity ofthe point image in the first embodiment.

FIG. 7 is a side view of the handheld blur evaluating apparatusaccording to the first embodiment.

FIG. 8 illustrates locus images in the first embodiment.

FIGS. 9A, 9B, 9C, and 9D are graphs of a handheld blur calculatingmethod according to the first embodiment.

FIG. 10 is a flowchart of a measuring method according to the firstembodiment.

FIG. 11 is a flowchart of a handheld blur calculating method accordingto the first embodiment.

FIG. 12 is an image stabilizing performance evaluation graph in thefirst embodiment.

FIG. 13 is a graph of the handheld blur calculating method (while animage stabilizing function is turned off) according to the firstembodiment;

FIGS. 14A and 14B explain object scanning control according to the firstembodiment.

FIG. 15 is a side view of a handheld blur evaluating apparatus accordingto a second embodiment.

FIGS. 16A and 16B explain a collimated light source according to thesecond embodiment.

FIG. 17 explains the handheld blur applied to the camera in the secondembodiment.

FIGS. 18A and 18B explain object scanning according to the secondembodiment.

FIG. 19 explains object scanning control according to the secondembodiment.

FIG. 20 is an object layout diagram in the second embodiment.

FIG. 21 is a locus image in the second embodiment.

FIG. 22 is an image stabilizing performance evaluation graph in thesecond embodiment.

FIG. 23 is a perspective view of a handheld blur evaluating apparatusaccording to a third embodiment.

FIG. 24 is a locus image in the third embodiment.

FIGS. 25A and 25B are extraction graphs of the locus of the center ofgravity of the point image in the third embodiment.

FIG. 26 is a flowchart of a handheld blur calculating method accordingto the third embodiment.

FIG. 27 is a schematic diagram of a handheld blur evaluating apparatusaccording to a fourth embodiment.

FIG. 28 is a block diagram of image evaluating unit in the fourthembodiment.

FIG. 29 is a graph of a reference image degradation amount in the fourthembodiment.

FIG. 30 is a graph of the reference image degradation amount in thefourth embodiment.

FIGS. 31A, 31B, and 31C explain a relationship between exposure time anddisturbance according to the fourth embodiment.

FIG. 32 explains an image contrast detecting method according to thefourth embodiment.

FIGS. 33A, 33B, 33C, and 33D explain a change amount calculating methodand disturbance superimposition at high ISO speed according to thefourth embodiment.

FIG. 34 explains the disturbance influence on the change amountaccording to the fourth embodiment.

FIG. 35 explains the disturbance influence on the change amountaccording to the fourth embodiment.

FIGS. 36A, 36B, and 36C explain the disturbance influence on a handheldblur amount according to the fourth embodiment.

FIG. 37 is a block diagram of a handheld blur evaluating unit accordingto a fifth embodiment.

FIGS. 38A and 38B explain a disturbance determining threshold by adetector according to the fifth embodiment.

FIGS. 39A, 39B, and 39C are flowcharts illustrating the operation of adetector according to the fifth embodiment.

FIGS. 40A, 40B, 40C, and 40D explain the determination of whether thereis disturbance according to the fifth embodiment.

FIGS. 41A, 41B, 41C, and 41D explain a correction method by a correctorin the fifth embodiment.

FIG. 42 explains a handheld blur evaluating unit according to a sixthembodiment.

FIGS. 43A and 43B are flowcharts illustrating the operation in thedetector in the sixth embodiment.

FIG. 44 is a schematic diagram of a handheld blur evaluating apparatusaccording to a seventh embodiment.

FIG. 45 is a plan view of a handheld blur measurement chart in theseventh embodiment.

FIG. 46 explains an image degradation amount according to the seventhembodiment.

FIGS. 47A and 47B illustrate a flowchart of the handheld blur evaluatingmethod in the seventh embodiment.

FIGS. 48A and 48B explain a relationship between a reference cameraimage and a chart image in the seventh embodiment.

FIG. 49 is a schematic diagram of the handheld blur evaluating apparatusaccording to the seventh embodiment.

FIGS. 50A and 50B are schematic diagrams of a handheld blur evaluatingapparatus according to an eighth embodiment.

FIGS. 51A and 51B illustrate a flowchart of a handheld blur evaluatingmethod according to the eighth embodiment.

FIG. 52 is a schematic diagram of a handheld blur evaluating apparatusaccording to a ninth embodiment.

FIGS. 53A and 53B are explanatory diagrams of a handheld blur evaluatingmethod according to the ninth embodiment.

FIGS. 54A and 54B explain the handheld blur evaluating method accordingto the ninth embodiment.

FIGS. 55A and 55B explain the handheld blur evaluating method accordingto the ninth embodiment.

FIGS. 56A and 56B explain the handheld blur evaluating method accordingto the ninth embodiment.

FIGS. 57A, 57B, 57C, and 57D explain a method for determining data or adata range according to the ninth embodiment.

DESCRIPTION OF THE EMBODIMENTS

In the following, the term “unit” may refer to a software context, ahardware context, or a combination of software and hardware contexts. Inthe software context, the term “unit” refers to a functionality, anapplication, a software module, a function, a routine, a set ofinstructions, or a program that can be executed by a programmableprocessor such as a microprocessor, a central processing unit (CPU), ora specially designed programmable device or controller. A memorycontains instructions or programs that, when executed by the CPU, causethe CPU to perform operations corresponding to units or functions. Inthe hardware context, the term “unit” refers to a hardware element, acircuit, an assembly, a physical structure, a system, a module, or asubsystem. Depending on the specific embodiment, the term “unit” mayinclude mechanical, optical, or electrical components, or anycombination of them. The term “unit” may include active (e.g.,transistors) or passive (e.g., capacitor) components. The term “unit”may include semiconductor devices having a substrate and other layers ofmaterials having various concentrations of conductivity. It may includea CPU or a programmable processor that can execute a program stored in amemory to perform specified functions. The term “unit” may include logicelements (e.g., AND, OR) implemented by transistor circuits or any otherswitching circuits. In the combination of software and hardwarecontexts, the term “unit” or “circuit” refers to any combination of thesoftware and hardware contexts as described above. In addition, the term“element,” “assembly,” “component,” or “device” may also refer to“circuit” with or without integration with packaging materials.

Referring now to the accompanying drawings, a detailed description willbe given of embodiments according to the disclosure.

First Embodiment

A description will now be given of a first embodiment according to thepresent disclosure. FIGS. 1A, 1B, and 1B are schematic diagrams of ahandheld blur evaluating apparatus 100 that performs a handheld blurevaluating method according to this embodiment. FIG. 1A is a side viewof the handheld blur evaluating apparatus 100. FIG. 1B is a top view ofthe handheld blur evaluating apparatus 100. FIG. 1C is a perspectiveview of the handheld blur evaluating apparatus 100. Reference numeral 11denotes a measurement camera (imaging unit), which is held by aphotographer. The measurement camera 11 faces a chart (object) 14. Achart image captured by the measurement camera 11 is input to a locuschange measuring unit (LCMU) 15. The locus change measuring unit 15detects the locus of the captured chart image and measures thedeterioration degree of the captured image caused by the camera handheldblur of the photographer.

This embodiment has two characteristics. First, the chart 14 can bescanned in a direction of an arrow 14 cP in FIG. 1B by an actuator(scanner) 14 b. Second, the chart 14 includes a point object 14 a, andthe locus change measuring unit 15 calculates the center of gravity ofthe point image captured by the measurement camera 11 at each scanningposition. Details of the above will be described below.

FIG. 2 is an image (locus image) captured by the measurement camera 11in a state where camera handheld blur occurs. In FIG. 2 , an image 21illustrates a locus of a point image 22 resulting from scanning of thepoint object 14 a during imaging. Reference numeral 22 a denotes thelocus of the center of gravity of the point image at each scanningposition. The locus change measuring unit 15 calculates the projectionof the image 22 in the horizontal direction and also calculates thecenter of gravity of the luminance at each horizontal position.

FIG. 3 is an extraction graph of the locus of the center of gravity ofthe point image binarized after the center of gravity of the image inFIG. 2 is obtained. In FIG. 3 , a horizontal axis represents ahorizontal pixel of an image sensor provided in the measurement camera11, and a vertical axis represents a vertical pixel of the image sensor.A waveform 31 is a locus waveform obtained by connecting the positionsof the centers of gravity of the vertical pixels of the point image inrespective horizontal pixels. By measuring a vertical amplitude 32 ofthe waveform 31, the handheld blur in the vertical direction of themeasurement camera 11 can be obtained.

FIG. 4 is a perspective view of the handheld blur evaluating apparatus100. As illustrated in FIG. 4 , the chart 14 can also be scanned in anarrow 14 cY direction, and while the measurement camera 11 is imagingthe chart 14, the chart 14 is scanned in the arrow 14 cY direction. FIG.5 illustrates a locus image at this time. In FIG. 5 , an image 51illustrates a locus of a point image 52 resulting from scanning of thepoint object 14 a during imaging. Reference numeral 52 a denotes a locusof the center of gravity of the point image at each scanning position.The locus change measuring unit 15 obtains the projection of the image52 in the vertical direction and obtains the center of gravity of theluminance at each vertical position. FIG. 6 is an extraction graph ofthe locus of the center of gravity of the point image binarized afterthe center of gravity of the image in FIG. 5 is obtained. In FIG. 6 , ahorizontal axis represents a horizontal pixel of the image sensorprovided in the measurement camera 11, and a vertical axis represents avertical pixel of the image sensor. A waveform 61 is a locus waveformobtained by connecting the positions of the centers of gravity of thehorizontal pixels of the point image in respective vertical pixels. Bymeasuring a horizontal amplitude 62 of the waveform 61, the handheldblur in the horizontal direction of the measurement camera 11 can beobtained.

FIG. 7 is a side view of the handheld blur evaluating apparatus 100, andillustrates an example in which the measurement camera 11 is fixed ontoa (vibration) excitation table ((vibration) excitation unit, vibrationunit) 12 instead of being held by the photographer. Based on (vibration)excitation waveform data 13, the excitation table 12 excites (vibrates)the measurement camera 11 around an arrow 12 aP and around an arrow 12aY orthogonal to the arrow 12 aP. The chart 14 is scanned in the arrow14 cP direction and the arrow 14 cY direction orthogonal to the arrow 14cP direction. The measurement camera 11 facing the chart 14 captures thechart 14 scanned during excitation by the excitation table 12. The chartimage of the measurement camera 11 is input to the locus changemeasuring unit 15, which detects the locus of the captured chart imageand measures the deterioration degree of the captured image due to thehandheld blur when the excitation is made with the excitation waveformdata 13.

The above example temporally shifts the imaging by the measurementcamera 11 caused by the scanning in the arrow 14 cP direction during theexcitation in the arrow 12 aP direction and the imaging by themeasurement camera 11 caused by the scanning in the arrow 14 cYdirection during the excitation in the arrow 12 aY direction. Therefore,the image 21 in FIG. 2 and the image 51 in FIG. 5 are different images.From the locus waveforms of the images 21 and 51, the handheld blur inthe measurement camera due to the excitation in the arrow 12 aPdirection and the handheld blur in the measurement camera due to theexcitation in the arrow 12 aY direction are obtained. Here, themeasurement camera 11 is excited in a direction (second direction)different from the arrows 14 cP and 14 cY, which are the scanningdirections (first directions) of the chart 14. Therefore, the imaging bythe measurement camera 11 caused by the scanning in the arrow 14 cPdirection during the excitation in the arrow 12 aP direction and theimaging by the measurement camera 11 caused by the scanning in the arrow14 cY direction during the excitation in the arrow 12 aY direction aresimultaneously performed. Thereby, loci 82P and 82Y of the point imageare recorded in a single image, as illustrated by an image 81 in FIG. 8as locus images. From two images obtained by trimming the image 81 withframes 83P and 83Y, locus waveforms are created as illustrated in FIGS.3 and 6 , and a handheld blur amount can be calculated in each of theexcitation directions 12 aP and 12 aY.

Referring now to FIGS. 9A, 9B, 9C, and 9D, a description will be givenof a method for acquiring a handheld blur amount for each exposure timeof the measurement camera 11 (handheld blur calculating method). FIGS.9A, 9B, 9C, and 9D are graphs of the handheld blur calculating method.In each of FIGS. 9A, 9B, 9C, and 9D, a horizontal axis represents ahorizontal pixel, and a vertical axis represents a vertical pixel.

FIG. 9A is a graph illustrating the handheld blur calculating method inwhich the locus waveform 31 in FIG. 3 is divided into a plurality ofcalculation areas 91 a to 91 d by exposure time of the measurementcamera 11. A description will now be given of a method of writing theexposure time together in FIG. 9A. A value obtained by multiplying theimaging magnification of the measurement camera 11 by the constantscanning speed of the chart 14 is the image plane speed on the imagesensor of the measurement camera 11. By dividing this image plane speedby the pixel size of the image sensor, the number of moving pixels pertime (pixel speed) can be obtained. Therefore, by multiplying theexposure time (for example, 1/60 seconds) by the pixel speed, the numberof moving pixels per exposure time can be obtained, so the number ofpixels on the horizontal axis in FIG. 9A can be associated with theexposure time.

FIGS. 9B and 9C are enlarged views of the locus waveform 31 divided bythe calculation area 91 a enclosed by a circle 92 in FIG. 9A. In FIG.9A, a plurality of calculation areas 91 a (for example, 1/60 seconds) to91 d (for example, ⅛ seconds) are separated from a calculation startingpoint 91. As illustrated in FIG. 9B, a handheld blur amount is obtainedby the number of pixels in a difference 93 between the maximum andminimum values of the locus waveform 31 at each exposure time (forexample, the calculation area 91 a). In another method, as illustratedin FIG. 9C, areas S1 and S2 where the locus waveform 31 divides arectangle 95 enclosed by the maximum and minimum values of the locuswaveform and the calculation area 91 a are obtained, and a smaller oneof the areas S1 and S2 is divided by the exposure time of thecalculation area 91 a to set the handheld blur amount. In FIG. 9B, asection 94 starting from the calculation starting point 91 is littlehandheld blurred, the image deterioration is little, and the handheldblur increases in a short time thereafter. In the case of such ahandheld blur, a handheld blur amount corresponding to the difference 93does not correctly represent the image deterioration caused by thishandheld blur. On the other hand, the method described with reference toFIG. 9C can obtain the handheld blur that reflects the curve of thehandheld blur during the exposure time.

In FIG. 9A, the handheld blur amount can be obtained in each of thedivided calculation areas 91 a to 91 d at once. Prior art requires themeasurement camera to capture images for respective exposure times, butthe method according to this embodiment does not require such work.Calculation areas 96 a to 96 d are set from a calculation starting point96 illustrated by a dashed line obtained by shifting the calculationstarting point 91 illustrated by the solid line set in FIG. 9A to theright by one pixel (FIG. 9D) and the handheld blur amount is calculatedfor each set exposure time. A handheld blur amount can be stablyobtained by averaging large handheld blur amount data obtained bysequentially shifting pixels in the section where the locus waveform 31is continuous in the measurement of FIG. 9D. Prior art acquires a largenumber of images using the measurement camera 11 at each exposure time,and obtains a handheld blur amount by processing the obtained images,but this embodiment does not require such work.

Prior art proposes a method of obtaining a handheld blur amount from animage degradation amount in an image captured by the measurement camera.However, this method has difficulty in accurately separating imagedegradation in an image peculiar to the measurement camera 11 that isnot being excited and image degradation in an image due to handheld blurin the measurement camera 11 that is being excited. On the other hand,as described with reference to FIGS. 9A, 9B, 9C, and 9D, this embodimentcan obtain an accurate handheld blur amount directly from the locuswaveform of the center of gravity of the point image.

FIG. 10 is a flowchart of a simple measuring method for imaging thechart 14 using the measurement camera 11. First, in step S1001, theexposure time is set for the measurement camera 11. In measuring thehandheld blur amount from exposure time of 1/60 seconds to exposure timeof 2 seconds, the exposure time is set to 4 seconds, which is double themaximum exposure time of 2 seconds. The brightness of the point object14 a in the chart 14 is adjusted by adjusting the illumination forproper exposure with the set exposure time, F-number, and ISO speed, orby attaching an ND filter to the imaging system of the measurementcamera 11.

Next, in step S1002, the image stabilizing function of the measurementcamera 11 is turned on. As described below, this embodiment does notrequire handheld blur amount measurement in a case where the imagestabilizing function is turned off. Next, in step S1003, the excitationtable 12 is operated to start exciting the measurement camera 11 in the12 aP and 12 aY directions. Next, in step S1004, the chart 14 is scannedin the 14 cP and 14 cY directions. Next, in step S1005, imaging isstarted with the measurement camera 11 that is being excited. Next stepS1006 is repeated until the imaging for four seconds, for example, iscompleted. After the imaging ends, this flow ends. Thereby, an imageillustrated in FIG. 8 can be acquired.

FIG. 11 is a flowchart of a handheld blur calculating method configuredto calculate the handheld blur in the measurement camera 11 from theimage obtained in the measurement flow of FIG. 10 . Each step in FIG. 11is mainly executed by the locus change measuring unit 15.

First, in step S1101, the image 81 in FIG. 8 is taken in. Next, in stepS1102, the image 81 is trimmed with frames 83P and 83Y. Next, in stepS1103, the positions of the centers of gravity of the point images inthe images of the frames 83P and 83Y are obtained, the locus waveforms31 and 61 illustrated in FIGS. 3 and 6 are extracted, and the locuswaveforms P and Y are set.

Next, in step S1104, the calculation starting point 91 of the handheldblur amount illustrated in FIG. 9A is set. Next, in step S1105, acalculation area for the handheld blur amount is set. More specifically,for the locus waveforms P and Y, as illustrated in FIG. 9A, the sectionof the first calculation area 91 a is set. Next, in step S1106, thehandheld blur amounts of the locus waveforms P and Y in the setcalculation area are obtained using the method illustrated in FIG. 9C.Next, in step S1107, the mean square of the handheld blur amounts P andY is calculated and a handheld blur amount PY is calculated andrecorded.

Next, in step S1108, it is determined whether or not the handheld bluramount calculation for the set calculation areas has been completed. Ina case where the handheld blur amount calculation has not yet beencompleted, the flow returns to step S1105 to set the next section (forexample, the second calculation area 91 b in FIG. 9A), and to record thehandheld blur amount PY in that calculation area in step S1107. Afterthe handheld blur amounts PY of all calculation areas 91 a to 91 d(exposure times) in FIG. 9A are recorded, the flow proceeds to stepS1109.

In step S1109, the next calculation starting point is set. That is, thecalculation starting point 96 in FIG. 9D is set. Next, in step S1110, itis determined whether or not the handheld blur amount PY of each of allcalculation areas at the set calculation starting point has beencompletely calculated. In a case where there is an uncalculated startingpoint, the flow returns to step S1105 to continue the handheld bluramount calculation. In a case where the calculation of the handheld bluramount PY of each calculation area at all calculation starting points iscompleted, the flow proceeds to step S1111. In step S1111, an averagehandheld blur amount PY is obtained by averaging the recorded handheldblur amounts PY for respective calculation starting points by dividedcalculation area.

FIG. 12 is an image stabilizing performance evaluation graphillustrating the average handheld blur amount PY obtained by the abovehandheld blur calculation. In FIG. 12 , a horizontal axis representsexposure time and, for example, the calculation areas 91 a to 91 d ofthe exposure times in FIG. 9A are arranged in order corresponding to theexposure time. On the horizontal axis, the exposure time increasestoward the right. A vertical axis represents the average handheld bluramount PY. A solid curve 1201 illustrates the average handheld bluramount PY curve obtained by the flow of FIG. 11 , and a residue amountof the image stabilization in a case where the image stabilizingfunction of the measurement camera 11 is turned on. A broken curve 1202illustrates a handheld blur amount in a case where the image stabilizingfunction is turned off. The curve 1202 is not the result obtained fromthe measurement camera 11 but a theoretical curve obtained by plottingtheoretically obtained numerical values. The reason why the theoreticalcurve can be used will be described below.

As mentioned above, the handheld blur amount can be obtained using thelocus waveform of the center of gravity of the point image. Thus, theoptical performance and image processing peculiar to each model of thecamera do not affect the handheld blur amount, and the image stabilizingperformance can be exclusively evaluated. In a case where the imagestabilizing function is turned off, the handheld blur amount based onthe excitation waveform data 13 of the excitation table 12 can beobtained for any camera and it is unnecessary to measure the handheldblur amount for each camera in a case where the image stabilizingfunction is turned off. The theoretical curve 1202 is obtained inaccordance with the following items (1) to (5) similarly to steps S1104and subsequent steps in FIG. 11 .

(1) By multiplying the excitation waveform data 13, which is angulardata around 12 aP and 12 aY in FIG. 7 , by the focal length of themeasurement camera, locus waveforms 1301P and 1301Y illustrating thehandheld blur amounts on the image plane can be determined. A graph ofthe handheld blur calculating method in a case where the imagestabilizing function is turned off in FIG. 13 illustrates only the locuswaveform 1301P.

(2) A calculation starting point 1302 is set, and handheld blur amountsP and Y in calculation areas 1302 a to 1302 d from the calculationstarting point 1302 are obtained from the locus waveforms 1301P and1301Y, respectively.

(3) A handheld blur amount PY is obtained by calculating the mean squareof the handheld blur amounts P and Y.

(4) By shifting the calculation starting point, the handheld blur amountin each of the calculation areas 1302 a to 1302 d is obtained from thelocus waveforms 1301P and 1301Y.

(5) By averaging the handheld blur amounts PY for respective calculationstarting points by calculation area, the average handheld blur amount PYis calculated.

Exposure times A and B are read from the graph, which are intersectionsbetween the theoretical curve 1202 of FIG. 12 obtained by the abovecalculation and a predetermined permissible handheld blur amountthreshold 1203 and between the average handheld blur amount PY curve1201 obtained where the image stabilizing function is turned on and thepredetermined permissible handheld blur amount threshold 1203. Thelonger a distance 1204 between the exposure times A and B becomes, thehigher the image stabilizing performance becomes.

A description will now be given of a function that improves themeasurement accuracy. In a case where a positional relationship shiftsbetween the positions of the loci 82P and 82Y of the point imageillustrated in FIG. 8 and the frames 83P and 83Y, the point image cannotbe accurately trimmed. In addition, the locus shape of the point imageobtained in a case where the loci 82P and 82Y of the point image areprojected at the central portion of the image 81, and the locus shape ofthe point image obtained in a case where the loci 82P and 82Y of thepoint image are projected at the peripheral portion of the image 81 maybe different due to the optical distortion. Thus, this embodiment has afunction for always projecting the loci 82P and 82Y of the point imageat the same position on the image 81.

FIGS. 14A and 14B explain object scanning control. In FIG. 14A, arelease signal as an imaging start signal of the measurement camera 11is input to a scanning command unit 1401 serving as a measurementsynchronizer. The scanning command unit 1401 receives the release signaland instructs the actuator 14 b to scan the chart 14. Synchronizing theimaging start timing and the chart scanning timing in this manner canalways keep constant the positional relationship between the loci 82Pand 82Y of the point image and the image 81. Since constant-speedscanning is not performed for a while after the scanning of the chart 14starts, the correct exposure time cannot be set in that section.Accordingly, the calculation starting point 91 illustrated in FIG. 9D isset within the constant-speed scanning section, and the handheld bluramount is not calculated for the locus waveform 31 a during scanningacceleration.

In FIG. 14B, a position detector 1402 for detecting a scanning positionof the chart 14 is provided. The position detector 1402 serves as ameasurement synchronizer, and sends to the measurement camera 11 theposition at which the chart 14 is scanned at a constant speed. Themeasurement camera 11 performs imaging at the timing output from theposition detector 1402. Even such a configuration can always keepconstant the positional relationship between the image 81 and the loci82P and 82Y of the point image. Since the chart is not imaged duringscanning acceleration, the calculation starting point 91 can be set atthe start point of the locus waveform 31, and the calculated handheldblur amount can be increased. Thus, calculating the handheld blur amountusing the locus waveform obtained from the center of gravity in thelocus of the point image enables the handheld blur of the camera to bemore accurately evaluated and the measurement time to be significantlyreduced.

Thus, the handheld blur evaluating apparatus 100 according to thisembodiment includes a scanner (actuator 14 b) configured to scan anobject (chart 14) as a point object 14 a, and an imaging unit(measurement camera 11) configured to image the object that is beingscanned. The handheld blur evaluating apparatus 100 further includes a(vibration) excitation unit (excitation table 12) configured to excitethe imaging unit in a direction (second direction, i.e., excitationdirection) different from the scanning direction (first direction) ofthe object. The handheld blur evaluating apparatus 100 further includesa locus change measuring unit 15 configured to measure the handheld blurof the imaging unit based on the locus change (loci 22 and 52 of thepoint image) relating to the excitation direction of the object imagecaptured by the imaging unit. The handheld blur evaluating apparatus 100evaluates the handheld blur of the imaging unit based on the output ofthe locus change measuring unit 15. More specifically, the locus changemeasuring unit 15 obtains the locus waveforms 31 and 61 from the locusof the center of gravity of the point image of the object image (stepS1103 in FIG. 11 ), and obtains the handheld blur amount from theobtained locus waveform.

The locus change measuring unit 15 divides the locus waveforms 31 and 61into a plurality of calculation areas, and obtains the handheld bluramount for each of the plurality of calculation areas (91 a to 91 d).The locus change measuring unit 15 obtains the sections of the pluralityof calculation areas from the exposure time of the imaging unit(measurement camera 11). The locus change measuring unit 15 moves theplurality of calculation areas (shifts the calculation starting point91) and obtains the handheld blur amount in each movement area. Thehandheld blur evaluating apparatus 100 includes a measurementsynchronizer (scanning command unit 1401, position detector 1402)configured to synchronize the imaging by the imaging unit (measuringcamera 11) and the scanning by the scanner (actuator 14 b). Themeasurement synchronizer (scanning command unit 1401) controls thescanner (actuator 14 b) based on the imaging timing of the imaging unit(measurement camera 11). The measurement synchronizer (position detector1402) controls the imaging of the imaging unit (measurement camera 11)in synchronization with the position of the object (chart 14) scanned bythe scanner (actuator 14 b).

Second Embodiment

A description will now be given of a second embodiment according to thepresent disclosure. FIG. 15 is a side view of a handheld blur evaluatingapparatus 100 a that performs a camera handheld blur amount measuringmethod according to this embodiment. The handheld blur evaluatingapparatus 100 a is different from the handheld blur evaluating apparatus100 of the first embodiment that has the point object 14 a in that thehandheld blur evaluating apparatus 100 a includes a collimated lightsource 1501 a and a point light source 1501 b. The chart 14 isrotationally scanned in arrows 1502P and 1502Y directions around avirtual axis 1503, which is a principal point position or an aperturestop position of the measurement camera 11.

A description will now be given of the reason for using the collimatedlight source 1501 a and the point light source 1501 b instead of thechart 14. FIGS. 16A and 16B explain the collimated light source. FIG.16A is a sectional view of the collimated light source 1502 a thatincludes a lens barrel 1601, a lens 1602 fixed to the lens barrel 1601,and a light source 1603 disposed at a focal length position of the lens1602. Since the light source is provided at the focal length position ofthe lens, a light beam (luminous flux) emitted from the light sourcepasses through the lens 1602 and becomes parallel light (collimatedlight). Since the parallel light is an object light source at theinfinity position, the imaging magnification of the measurement camera11 becomes extremely small.

The handheld blur applied to the camera includes rotational handheldblur 1701 and shift handheld blur 1702 illustrated in FIG. 17 , and thehandheld blur of the imaging plane caused by the shift handheld blur1702 is negligible in a case where the imaging magnification of themeasurement camera 11 is small. Therefore, using the collimated lightsource 1502 a can measure only the handheld blur amount caused by therotational handheld blur. As illustrated in FIG. 16B, the point lightsource 1501 b has a configuration in which the lens 1602 in FIG. 16A isremoved. The handheld blur amount is measured as a mixture of the shifthandheld blur and rotational handheld blur according to the imagingmagnification of the measurement camera 11 relative to the point lightsource 1502 b. Only the handheld blur amount caused by the shifthandheld blur can be obtained from a difference between the locuswaveform obtained from the collimated light source 1502 a and the locuswaveform obtained from the point light source 1502 b. Thus, the handheldblur amount caused by the rotation handheld blur and the handheld bluramount caused by the shift handheld blur can be separated, and the imagestabilizing performance for each handheld blur can be evaluated.

A description will now be given of the reason why the chart 14 isrotationally scanned around the virtual axis 1503 in the arrows 1502Pand 1502Y directions unlike the first embodiment. The collimated lightsource 1502 a is the object light source at infinity position and doesnot change the light source position on the imaging plane in themeasurement camera 11 even if linear scanning is performed as in thefirst embodiment, and a locus waveform cannot be obtained. The locuswaveform can be obtained by rotationally scanning the collimated lightsource 1502 a. However, in a case where rotational scanning is performedaround the position 1801 of the collimated light source, the emittedlight source causes optical shielding as illustrated in FIG. 18A, andthe locus waveform having a sufficient length cannot be obtained on theimage plane 11 a. On the other hand, as illustrated in FIG. 18B, in acase where the collimated light source 1502 a is rotationally scannedabout the virtual axis 1503, the shielding influence can be reduced, andthe locus waveform having a sufficient length can be obtained on theimage plane 11 a. Since the point light source 1502 b can obtain a locuswaveform having a sufficient length on the image plane for both linearscanning and rotational scanning, the point light source 1502 b may beintegrated with the collimated light source 1502 a to perform rotationalscanning.

This embodiment performs rotational scanning about the virtual axis 1503by linearly scanning and rotationally scanning the collimated lightsource. FIG. 19 explains object scanning control, and simply illustratesthe configuration. A linear scanning actuator as a linear scanner 1902scans a linear scanning table 1901 in an arrow 1901 a direction. Arotational scanning table 1903 provided on the linear scanning table1901 is rotationally scanned on the linear scanning table 1901 in anarrow 1903 a direction about an axis 1903 b by a rotational scanningactuator as a rotary scanner 1904. The cooperation of the linearscanning and rotational scanning causes the collimated light source 1502a to be scanned to 1502 a′ illustrated by a dotted line. This isapproximately equivalent to rotationally scanning (arrow 1905) thecollimated light source 1502 a around the virtual axis 1503. Moreprecisely, a distance between the collimated light source 1502 a and themeasurement camera 11 slightly changes (by a gap 1906) along with therotational scanning, but the distance change does not matter because ofthe infinity light source.

The position detector 1402 continuously detects the position of thelinear scanning table 1901, and controls the imaging timing of themeasurement camera 11 similarly to FIG. 14 . A rotation control unit1904 a is provided for controlling a rotation angle of the rotationalscanning table 1903 by the rotary scanner 1904 based on a positiondetection output of the position detector 1402. Hence, the position ofthe virtual axis (rotation axis) 1503 can be changed by adjusting arelationship between the output of the position detector 1402 and therotational scanning amount of the rotary scanner 1904 through therotation control unit 1904 a. The position of the linear scanning table1901 in an arrow 1907 direction can be changed. By adjusting thepositions of the rotation control unit 1904 a and the arrow 1907, thecollimated light source 1502 a can be optimally rotationally scannedaccording to the optical characteristic of the measurement camera 11.For example, a wide lens with a short focal length can reduce the radiusof rotation for rotational scanning, and a telephoto lens with a longfocal length can increase the radius of rotation for rotationalscanning.

FIG. 20 is an object layout diagram of the chart 14 in FIG. 15 viewedfrom the measurement camera 11 side. On the chart 14, collimated lightsources 1502 aP and 1502 aY and point light sources 1502 bP and 1502 bYare provided. The collimated light source 1502 aP and the point lightsource 1502 bP are integrally rotationally scanned in an arrow 2001Pdirection (where the arrow becomes a straight line in the direction ofFIG. 20 ). The collimated light source 1502 aY and the point lightsource 1502 bY are integrally rotationally scanned in the arrow 2001Ydirection (where the arrow becomes a straight line in the direction ofFIG. 20 ).

FIG. 21 illustrates locus images of the point images of the collimatedlight sources and the point light sources in FIG. 20 captured by themeasurement camera 11. An image 2101 has a point image locus 2102 aP ofthe collimated light source 1502 aP, a point image locus 2102 bP of thepoint light source 1502 bP, a point image locus 2102 aY of thecollimated light source 1502 aY, and a point image locus 2102 bY of thepoint light source 1502 bY. Each point image locus is trimmed similarlyto FIG. 8 , and the average handheld blur amount PY can be obtainedsimilarly to the first embodiment.

FIG. 22 , similarly to FIG. 12 , illustrates an image stabilizingperformance evaluation chart obtained in this embodiment, andillustrates the average handheld blur amount PY. A solid curve 2201 a isthe average handheld blur amount PY curve obtained by the collimatedlight source 1502 a, and the solid curve 2201 b is an average handheldblur amount PY curve obtained by the point light source 1502 b. Exposuretimes A, B, and C are read from the graph, which are intersectionsbetween the theoretical curve 1202 in a case where the image stabilizingfunction is turned off and the predetermined permissible handheld bluramount threshold 1203, between the average handheld blur amount PY curve2201 a in a case where the image stabilizing function is turned on andthe predetermined permissible handheld blur amount threshold 1203, andbetween the average handheld blur amount PY curve 2201 b in a case wherethe image stabilizing function is turned on and the predeterminedpermissible handheld blur amount threshold 1203. The image stabilizingperformance without shift handheld blur can be evaluated based on adistance between the exposure times A and B, and the image stabilizingperformance evaluation with the shift handheld blur can be evaluatedbased on a distance between the exposure times A and C.

This embodiment has described camera handheld blur evaluation(evaluation of image stabilizing performance) using an example in whichthe measurement camera 11 is excited by the excitation table 12, but isnot limited to the excitation table 12 and the photographer may grip themeasurement camera 11 and evaluate the image stabilizing performancethrough his manual handheld blur. In this case, the theoretical curve1202 may be used for a state in which the image stabilizing function isturned off, or the photographer may create a measurement curve in whichthe image stabilizing function of the measurement camera 11 is turnedoff. The camera handheld blur may be more accurately evaluated and themeasurement time can be significantly reduced by obtaining the handheldblur amount using the locus waveform obtained from the locus of thecenter of gravity of the point image. A handheld blur amount caused onlyby the angular handheld blur can be accurately obtained by using acollimated light source as a point object.

As described above, the handheld blur evaluating apparatus 100 aaccording to this embodiment includes a scanner (actuator 14 b)configured to scan an object (chart 14) as a point object 14 a, and animaging unit (measurement camera 11) configured to image the object thatis being scanned. The handheld blur evaluating apparatus 100 a includesa (vibration) excitation unit (excitation table 12) configured to excitethe imaging unit in a direction different from the scanning direction ofthe object. The handheld blur evaluating apparatus 100 a furtherincludes a locus change measuring unit 15 configured to measure thehandheld blur of the imaging unit based on the locus change in theobject image captured by the imaging unit (point image loci 2102 aP,2102 bP, 2102 aY, and 2102 bY). The handheld blur evaluating apparatus100 a evaluates the handheld blur of the imaging unit based on theoutput of the locus change measuring unit 15. More specifically, theobject (chart 14) is a collimated light source, and the locus changemeasuring unit 15 obtains the handheld blur amount from the locuswaveform obtained from the locus of the center of gravity of the objectimage. The scanner (linear scanner 1902 and rotary scanner 1904)rotationally scans the object (chart 14) with the imaging unit about thevirtual axis (central axis) 1503. The handheld blur evaluating apparatus100 a further includes the rotation control unit 1904 a configured tochange the radius of rotation of the scanner.

Third Embodiment

A description will now be given of a third embodiment according to thepresent disclosure. FIG. 23 is a perspective view of a handheld blurevaluating apparatus 100 b according to this embodiment. As describedwith reference to FIG. 7 , the first embodiment includes the chart 14that has a point object scanned in the arrow 14 cP direction and a pointobject scanned in the arrow 14 cY direction, and calculates a handheldblur amount from the loci. On the other hand, this embodimentillustrated in FIG. 23 scans a point object 2301 in an arrow 2302direction tilted by −45 degrees relative to the handheld blur directiongenerated by the excitation directions 12 aP and 12 aY of the excitationtable 12. The measurement camera 11 is excited based on the sameexcitation waveform data in the arrows 12 aP and 12 aY directionsaccording to the excitation table 12, so that the combined excitation isperformed around an excitation axis (combined excitation axis) 12 aPY.

Thus, orthogonally combining the scanning direction and the combinedexcitation axis can provide a locus image 2401 in FIG. 24 similarly toFIG. 3 , and a locus waveform 2501 a illustrated in FIG. 25A is obtainedfrom the locus image. The coordinate transformation by 45° is performedfor the locus waveform 2501 a to provide a locus waveform 2501 billustrated in FIG. 25B. A handheld blur amount is obtained by themethod described with reference to FIG. 9 from the obtained locuswaveform 2501 b. Since the locus waveform 2501 b includes handheld blursin the excitation directions 12 aP and 12 aY of the excitation table 12mixed as the excitation direction (excitation axis 12 aPY), there is noneed to take the mean square of the handheld blurs in the two directionsunlike the first and second embodiments.

FIG. 26 is a flowchart of a handheld blur calculating method that isused by the locus change measuring unit 15 to calculate the handheldblur in the measurement camera 11 from the locus image 2401 in thisembodiment. FIG. 26 illustrates a flow that omits the handheld blurcalculation in two directions and the mean squares in FIG. 11 . Hence,calculation processing can be simplified by scanning the point object ina direction different from the two handheld blur directions generated inthe measurement camera 11 caused by the excitation of the excitationtable 12.

As described above, the handheld blur evaluating apparatus 100 baccording to this embodiment includes the scanner (actuator 14 b)configured to scan an object (chart 14) as the point object 14 a, andthe imaging unit (measurement camera 11) configured to image the objectthat is being scanned. The handheld blur evaluating apparatus 100 bfurther includes the excitation unit (excitation table 12) configured toexcite the imaging unit, and the locus change measuring unit 15configured to measure the camera handheld blur based on the locus changein the object image (locus 2302 of the point image) captured by theimaging unit. The handheld blur evaluating apparatus 100 b evaluates thehandheld blur of the imaging unit based on the output of the locuschange measuring unit 15. The scanner (actuator 14 b) scans the object(chart 14) in a direction different from the plurality of excitationdirections (12 aP and 12 aY) of the excitation table 12. Morespecifically, the scanner (actuator 14 b) scans the object (chart 14) ina direction orthogonal to the excitation axis 12 aPY in the combinedexcitation direction (combined direction) of the plurality of excitationdirections (12 aP and 12 aY).

Fourth Embodiment

A description will be given of a fourth embodiment according to thepresent disclosure. FIG. 27 is a schematic diagram of a handheld blurevaluating apparatus 100 c that performs a camera handheld blur amountmeasuring method according to this embodiment. In FIG. 27 , referencenumeral 11 denotes a measurement camera (imaging unit), which isinstalled on a (vibration) excitation table (excitation unit) 12. Theexcitation table 12 excites (vibrates) the measurement camera 11 aboutan arrow 12 aP based on excitation waveform data 13. The excitationtable 12 can be controlled to switch a driving state (that is, betweenan excitation state and a stationary (non-excitation) state). Themeasurement camera 11 faces a chart 14 as an object, and a chart imagecaptured by the measurement camera 11 during excitation by theexcitation table is input to an image evaluating unit 271. The imageevaluating unit 271 detects the contrast of the captured chart image andmeasures the deterioration degree of the captured image caused by the(vibration) excitation. The details of the evaluation method are alsodisclosed in the image evaluating method in the prior art, and adescription thereof will be omitted.

Referring now to FIG. 28 , a description will be given of the operationof the image evaluating unit 271. FIG. 28 is a block diagram of theimage evaluating unit 271. In FIG. 28 , a stationary-state(non-excitation-state) output 282 includes image data at the stationarytime (measurement data at the stationary time) captured by themeasurement camera 11 while the excitation table 12 is in the stationarystate with a plurality of exposure times or luminances. Anexcitation-state output 281 includes image data at the excitation time(measurement data at the excitation time) captured by the measurementcamera 11 while the excitation table 12 is in an excitation state with aplurality of exposure times or luminances.

The image evaluating unit 271 calculates information such as a handheldblur amount and an image degradation (bokeh) amount as anexcitation-state change amount (excitation-state measurement data) 283based on the excitation-state output 281 that has been input. Similarly,the image evaluating unit 271 calculates a stationary-state changeamount (stationary-state measurement data) 284 such as a handheld bluramount and an image degradation amount based on the stationary-stateoutput 282 that has been input. The handheld blur amount and the imagedegradation amount at the stationary time are generally referred to as areference image degradation amount, and therefore will be uniformlyreferred to as a reference image degradation amount in thisspecification. A change amount such as the image degradation amount andthe handheld blur amount measured at the excitation time will beuniformly referred to as an total image degradation amount in thisspecification.

The obtained total image degradation amount 283 and stationary-statemeasurement data 284 are compared by a divider 285, and handheld bluramount data 286 is calculated by calculation processing such assubtraction. The handheld blur amount data 286 corresponds to handheldblur amount data in the claims. The handheld blur is evaluated by anevaluation block 287 based on this handheld blur amount data 286.

Here, camera handheld blur is applied to the measurement camera 11 evenin a case where the excitation table 12 is in the stationary state. Thecauses of camera handheld blur include driving the shutter, mirrors, andlenses inside the measurement camera 11, and irregular vibrations inputto the measurement environment from the outside, such as building andfloor shakes. In addition to the camera handheld blur, in a case wherethe ISO speed is increased, noise that does not appear in the actualphenomenon may be superimposed on an image. Camera handheld blur causedby shutter, mirror, and lens driving inside the measurement camera 11,the irregular vibrations input to the measurement environment from theoutside, such as building and floor shakes, and noise superimpositiondue to the high ISO speed may become disturbances in calculating achange amount and cause erroneous calculation of the handheld bluramount. A description will now be given of the disturbance influence onthe reference image degradation amount and the total image degradationamount using the reference image degradation amount as a target.

FIG. 29 is a graph illustrating a reference image degradation amount inorder of exposure time in a case where there is no camera handheld bluror disturbance. In the graph of FIG. 29 , a horizontal axis representsexposure time, which increases toward the right. A vertical axisrepresents the reference image degradation amount, which increases asthe position goes up. The unit of the vertical axis is, for example, thenumber of imaging pixels of the image sensor in the measurement camera11. As illustrated in FIG. 29 , in a reference image degradation amountwaveform 291, the reference image degradation amount generally increasesas the exposure time increases. This is because noise is superimposed ona captured image of a dark object that requires a long exposure time.

FIG. 30 is a graph illustrating a reference image degradation amount inorder of exposure time in a case where there is camera handheld blur ordisturbance. In a reference image degradation amount waveform 301, thetendency of a reference image degradation amount 301 a significantlychanges at a specific exposure time 302. Although not illustrated, sucha phenomenon also occurs in an total image degradation amount waveform.A reference image degradation amount, an total image degradation amount(excitation-state bokeh amount), or a handheld blur amount representinga sudden change at a singular point will be referred to as a singular(anomalous) change amount. A specific exposure time that significantlychanges the tendency of the change amount will be referred to as aspecific exposure time (specific imaging condition). In order to avoiddescription confusion, a singular change amount generated in a referenceimage degradation amount waveform will be referred to as a singularimage degradation amount, a singular change amount generated in an totalimage degradation amount waveform will be referred to as a singulartotal image degradation amount, and a singular change amount generatedin handheld blur amount data will be referred to as a singular handheldblur amount.

FIGS. 31A, 31B, and 31C illustrate camera handheld blur waveforms inmeasuring a reference image degradation amount, where a horizontal axisrepresents elapsed time and a vertical axis represents a handheld bluramount on an imaging plane. The unit of the vertical axis is the numberof imaging pixels similarly to FIGS. 29 and 30 . As illustrated in FIG.31A, a camera handheld blur waveform 311 has a large camera handheldblur 311 a in the first half of exposure 312 a and a small camerahandheld blur 311 b in the second half of exposure 312 b. In this case,since the exposure time 312 is long, a ratio of the camera handheld blur311 b is large and the influence of the camera handheld blur 311 a issmall. Therefore, the reference image degradation amount is notsignificant. In FIG. 31B, the exposure time 312 is short relative to thecamera handheld blur 311 a, so the reference image degradation amount isnot significant. However, in FIG. 31C, the exposure time 312 isapproximately as long as a duration in which the maximum and minimumvalues of the camera handheld blur 311 a occur. Thus, the referenceimage degradation amount becomes significant due to the camera handheldblur generated during exposure, and becomes a singular image degradationamount. In this way, a singular image degradation amount occurs in aspecific exposure time due to the camera handheld blur. Even in the caseof irregular disturbance vibration, a similar phenomenon occursdepending on the timing with the exposure time.

Referring now to FIGS. 32 and 33 , a description will be given of thedisturbance superimposition that occurs in a case where the ISO speedbecomes high using the reference image degradation amount as a target.FIG. 32 explains a method of obtaining a reference image degradationamount from an image captured by the measurement camera 11. In order todetect the image contrast described above, a black-and-white chart 14illustrated in FIG. 32 is used.

FIG. 33A is a graph illustrating luminance changes in the horizontaldirection in an image of the chart 14 captured without camera handheldblur. A horizontal axis represents a black-and-white boundary line ofthe chart 14 and pixels in the normal direction on the image sensor, anda vertical axis represents normalized pixel luminance in the normaldirection. This luminance is detected by a luminance extraction line 330in a captured image. As illustrated in FIG. 33A, a luminance changewaveform 331 has a predetermined slope 331 a in a range that includes aboundary between white and black. A luminance change width 332 thatexcludes the upper and lower limits of 20% is set to a reference imagedegradation amount. In the case where there is the camera handheld bluras illustrated in FIG. 31C, a luminance change waveform 331 illustratedin FIG. 33B is obtained, and the luminance change width 332 becomeswider. Therefore, the reference image degradation amount increases.

A description will now be given of a relationship between the imagingsensitivity (ISO speed) and the reference image degradation amount. FIG.33C illustrates the state of the chart 14 in imaging at low luminancewith high sensitivity. In this state, the luminance varies in a casewhere the chart is illuminated at low luminance. Slight contrast changesin the chart are increased for high-sensitivity imaging. Thereby, chartirregularity 14 d appears on the chart 14.

FIG. 33C illustrates an imaging result in a state where there is nocamera handheld blur or disturbance vibration, and an irregular peakindicated by 331 b may appear in the luminance change waveform 331 dueto the chart irregularity 14 d. Since the width of the irregular peak331 b is smaller than the luminance change width 332, it is treated asnoise. Therefore, the obtained reference image degradation amount is notmuch different from the reference image degradation amount obtained byimaging with normal sensitivity.

FIG. 33D illustrates an imaging result in a case where there is camerahandheld blur or disturbance vibration, and an irregular peak indicatedby 331 b may appear in the luminance change waveform 331 due to thechart irregularity 14 d. As described with reference to FIG. 33B, sincethe irregular peak 331 b caused by the chart irregularity 14 d isincluded in the luminance change width 332, the luminance change width332 becomes wider. Therefore, in high-sensitivity imaging at a specificexposure time, a singular image degradation amount appears due to camerahandheld blur or disturbance vibration.

FIG. 34 illustrates an imaging result of a chart with normal luminance.FIG. 34 is a graph illustrating a reference image degradation amount inorder of exposure time in a case where there is camera handheld blur ordisturbance vibration. A reference image degradation amount waveform 341has a slightly larger reference image degradation amount 341 a at aspecific exposure time 340.

FIG. 35 illustrates an imaging result of a chart illuminated with lowluminance with high sensitivity (high ISO speed). FIG. 35 is a graphillustrating a reference image degradation amount in order of exposuretime in a case where there is camera handheld blur or disturbancevibration. A reference image degradation amount waveform 351 has asingular handheld blur amount 351 a at a specific exposure time 340.Thus, a singular image degradation amount different from a referenceimage degradation amount appears at a specific exposure time due to animaging condition such as the imaging sensitivity, camera handheld blur,or disturbance vibration.

As described above, in order to evaluate the handheld blur in themeasurement camera 11, the image evaluating unit 271 obtains a referenceimage degradation amount while the excitation table 12 is in thestationary state, and subtracts it from an total image degradationamount obtained from the image evaluating unit 271 in the handheld blurstate. Now assume that the measurement camera 11 has an imagestabilizing function. At this time, camera handheld blur and disturbancevibration are reduced by the image stabilization.

FIG. 36A illustrates an total image degradation amount at each exposuretime captured in a case where the measurement camera 11 that is turningon the image stabilizing function is excited and handheld blurred. InFIG. 36A, a horizontal axis represents exposure time, and a verticalaxis represents an total image degradation amount. An total imagedegradation amount waveform 361 does not generate a singular imagedegradation amount due to the image stabilizing function. A handheldblur amount waveform 362 illustrated in FIG. 36C is obtained bysubtracting the reference image degradation amount illustrated in FIG.36B from the obtained total image degradation amount. In FIG. 36B, sincethere is a singular handheld blur amount at the exposure time 340, ahandheld blur amount obtained by the subtraction also has a singularhandheld blur bottom. Therefore, the handheld blur amount becomes smallat the exposure time 340. A handheld blur amount in FIG. 36C representsa residue handheld blur amount after the image stabilizing functionworks, but the image stabilizing performance is incorrectly evaluated atthe specific exposure time 340. This would result in inaccurateevaluation of the image stabilizing performance, and thus thecountermeasure of the singular image degradation amount may be taken.

Fifth Embodiment

A description will be given of a fifth embodiment according to thedisclosure. Referring now to FIG. 37 , a description will be given of anoperation of an image evaluating unit 271 according to this embodiment.FIG. 37 is a block diagram of the image evaluating unit 271. FIG. 37 isbased on FIG. 28 , and thus a description of common portion will beomitted by designating the same reference numerals.

Reference numeral 371 in FIG. 37 denotes a detector configured to detectdisturbance. The detector 371 includes a processing unit A373 thatprocesses data of an total image degradation amount in a case where thetotal image degradation amount is input, and a processing unit B374 thatprocesses data of a reference image degradation amount in a case wherethe reference image degradation amount is input. A determination unit375 determines whether there is disturbance in the data processed by theprocessing units A373 and B374. The detector 371 transmits the result ofthe internal determination unit 375 to a switching unit 376. In a casewhere it is determined that there is no disturbance, the determinationunit 375 transmits an total image degradation amount 283 and a referenceimage degradation amount 284 to an A route, and a divider 372 calculatesa handheld blur amount. In a case where it is determined that there isdisturbance, the determination unit 375 transmits the total imagedegradation amount 283 and the reference image degradation amount 284 toa B route, and a corrector 377 performs correction processing for theseamounts, and then the divider 372 calculates a handheld blur amount.

Referring now to FIGS. 38A and 38B, a description will be given of athreshold that is used to determine the disturbance influence by thedetector 371 in FIG. 37 by using the reference image degradation amountas a target. Reference numeral 381 in FIG. 38A denotes a waveform graphwhere a horizontal axis represents exposure time and a vertical axisrepresents a reference image degradation amount. Reference numeral 382in FIG. 38A denotes a waveform graph illustrating a change rate of thereference image degradation amount of the waveform graph 381 relative toadjacent exposure times. +Th_a and −Th_a are thresholds for determiningthe disturbance influence. As indicated by 381, a monotonouslyincreasing waveform having no singular change amount exhibits a gentleslope as indicated by 382 in a case where the change rate is calculated,and the change rate does not exceed the thresholds.

Reference numerals 383 and 384 in FIG. 38B denote waveform graphssimilar to those in FIG. 38A. Reference numeral 383 a in FIG. 38Bdenotes a specific exposure time at which a singular handheld bluramount has occurred due to disturbance. In the waveform 383 in which thereference image degradation amount like such a singular point occurs, ina case where the change rate is calculated, the change rate having asteep slope is calculated as indicated by 384. The detector 371determines whether the change rate indicated by the specific exposuretime 383 a is equal to or higher than the (upper) threshold, anddetermines whether or not there is disturbance influence.

Referring now to FIGS. 39A, 39B, and 39C, a description will be given ofoperations of the processing units A373 and B374, and the determinationunit 375 installed in the detector 371 in FIG. 37 . FIG. 39A is aflowchart illustrating specific operation of the processing unit A373.In a case where the total image degradation amount is input to thedetector 371, the processing unit A373 starts the operation in stepS391.

In step S392, the processing unit A373 calculates the change rate of theinput reference image degradation amount. In a case where it isdetermined in step S393 whether the result of the change rate calculatedis less than the threshold, the result is recorded as Norm in step S394,and the flow ends in step S395. In a case where it is determined in stepS393 that the result of the change rate calculated is higher than thethreshold, the result is recorded as Err in step S396, at the same time,the exposure time at which the change rate is higher than the thresholdis recorded as Tv_A, and the flow ends.

FIG. 39B is a flowchart illustrating the operation of the processingunit B374. Since the basic operation is the same as that of theprocessing unit A373 illustrated in FIG. 39A, common portions will bedesignated by the same reference numerals and the details of thedescription will be omitted. After the change rate of the referenceimage degradation amount is calculated in step S397, in a case where theresult is less than the threshold, the result is recorded as Norm andthe flow ends. In a case where the result of the change rate of thereference image degradation amount is higher than the threshold, theresult is recorded as Err in step S398, and the exposure time at whichthe change rate is higher than the threshold is recorded as Tv_B.

FIG. 39C is a flowchart illustrating the operation of the determinationunit 375. After the processing units A373 and B374 have completed theiroperations, the determination unit 375 starts the operation in step S399based on the results of them. In step S3910, in a case where the resultsof the processing units A373 and B374 illustrated in FIGS. 39A and 39Bare both Norm indicating that both change rates are less than thethresholds, it is determined that there is no disturbance in step S3911,and the flow ends in step S3912. In a case where the result of stepS3910 is NO, the flow proceeds to step S3913 to determine whether theresults of both processing units A373 and B374 are Err indicating thatboth change rates are higher than the thresholds. In a case where theresult of step 3913 is YES, in step S3914, the exposure time Tv_A atwhich the change rate is higher than the threshold in the processingunit A373 is compared with the exposure time Tv_B at which the changerate is higher than the threshold in the processing unit B374. In a casewhere the exposure times Tv_A and Tv_B are the same exposure time, thereis environmental influence, the flow proceeds to step s3911, it isdetermined that there is no disturbance, and the flow ends.

In a case where the result of step S3914 is NO, the change rates arehigher than the thresholds at different exposure times, the flowproceeds to step S3915, it is determined that there is disturbance, andthe flow ends. In a case where the result of step S3913 is NO, one ofthe change rates is higher than the threshold, the flow proceeds to stepS3915, it is determined that there is disturbance, and the flow ends.

Referring now to FIGS. 40A, 40B, 40C, and 40D, a description will begiven of the determination of the presence and absence of disturbancedetermined in FIG. 39C. In FIG. 40A, a waveform graph 401 has ahorizontal axis that represents exposure time and a vertical axis thatrepresents a change rate calculated from the reference image degradationamount. A waveform graph 402 has a horizontal axis that representsexposure time and a vertical axis that represents a change ratecalculated from the total image degradation amount. Since both of thechange rates of the waveform graphs 401 and 402 are not higher than thethresholds, even if these data are used, the handheld blur amount can becalculated without disturbance influence.

Next, FIG. 40B will be described. A waveform graph 403 illustrated inFIG. 40B has a horizontal axis that represents exposure time and avertical axis that represents a change rate calculated from thereference image degradation amount. A waveform graph 404 has ahorizontal axis that represents exposure time and a vertical axis thatrepresents a change rate calculated from the total image degradationamount. Reference numeral 403 a denotes a specific exposure time atwhich the change rate is higher than the threshold. Both of the changerates of the waveform graphs 403 and 404 are higher than the thresholds,but the specific exposure times at which the change rates are higherthan the thresholds is the same specific exposure time 403 a. Even in acase where the handheld blur amount is calculated using these data, thesingular change amount occurs at the same exposure time 403 a, and theinfluences are canceled out. Therefore, the handheld blur amount withoutdisturbance influence can be calculated.

Next, FIG. 40C will be described. FIG. 40C is based on FIG. 40A, andcommon portions will be designated by the same reference numerals and adescription thereof will be omitted. In a waveform graph 405 illustratedin FIG. 40C, a horizontal axis represents exposure time, and a verticalaxis represents a change rate calculated from the reference imagedegradation amount. The change rate of the waveform graph 405 is higherthan the threshold, but the change rate of the waveform graph 402 is nothigher than the threshold. In calculating a handheld blur amount usingthese data, a handheld blur amount illustrated in FIG. 36C in whichdisturbance influence appears at a specific exposure time may becalculated. Therefore, in this case, it is determined that there isdisturbance, and the corrector 377 in FIG. 37 performs correctionprocessing for the reference image degradation amount higher than thethreshold. The data whose change rate is higher than the threshold isfirst data determined to have the disturbance. The data whose changerate is not higher than the threshold is second data determined to havethe disturbance.

Next, FIG. 40D will be described. Since FIG. 40D is based on FIG. 40B,corresponding elements will be designated by the same reference numeralsand a description thereof will be omitted. In a waveform graph 406illustrated in FIG. 40D, a horizontal axis represents exposure time, anda vertical axis represents a change rate calculated from the referenceimage degradation amount. Reference numeral 406 a denotes a specificexposure time at which the change rate is higher than the threshold.Both of the change rates of the waveform graphs 406 and 407 are higherthan the thresholds. The specific exposure times 406 a and 403 a atwhich the change rates are higher than the thresholds are different fromeach other. In calculating a handheld blur amount using these data, ahandheld blur amount illustrated in FIG. 36C in which the disturbanceinfluence appears at a specific exposure time may be calculated.Therefore, in this case, it is determined that there is disturbance, andthe corrector 377 in FIG. 37 performs correction processing for thereference image degradation amount and the total image degradationamount that are higher than the thresholds. The data in which the changerates are higher than the thresholds is the first data determined tohave the disturbance.

FIGS. 41A, 41B, 41C, and 41D sequentially describe several correctingmethods to be performed by the corrector 377 in FIG. 37 using thewaveform of the reference image degradation amount as a target.

(1) In FIG. 41A, a reference image degradation line obtained byaveraging the slopes of the reference image degradation amounts forrespective exposure times is set as a new reference image degradationamount. In FIG. 41A, a slope of a line connecting the reference imagedegradation amounts at exposure times 410 a and 4100 a of a referenceimage degradation waveform 412 is obtained (a ratio of adjacentreference image degradation amounts at the continuously changed exposuretimes is obtained). Similarly, the slope of the line connecting thereference image degradation amounts at the exposure times 4100 a and 410b is obtained. Thus, the slopes between all the exposure times areobtained, and an adjusted image degradation amount (straight line) 413having an average slope of those slopes is set, for example, by settingthe exposure time 410 a as a starting point, and an intercept of thestraight line and each exposure time is set to an adjusted imagedegradation amount. The adjusted image degradation amount 413corresponds to a correction change amount. Here, front and rearwaveforms 412 a and 412 b of a singular image degradation amount 412 chave steep slopes, but since these slopes have opposite directions, theyare canceled out by averaging. That is, the averaging of the slopes isless affected by the singular image degradation amount. A handheld bluramount can be stably obtained by using a difference between the adjustedimage degradation amount 413 and the total image degradation amount inFIG. 36A.

(2) A description will be given of a method illustrated in FIG. 41B.Since the waveforms 412 a and 412 b having slopes larger than an averageslope of the adjusted image degradation amount 413 can be found in FIG.41A, exposure time 4100 d for generating the singular image degradationamount can be found. Accordingly, in FIG. 41B, only the singular imagedegradation amount at the exposure time 4100 d is obtained by averagingthe adjacent exposure times 410 d and 410 e, and is set as an adjustedimage degradation amount 414 c. The adjusted image degradation amount414 c corresponds to a correction change amount. A handheld blur amountcan be stably obtained by using a difference between the adjusted imagedegradation amount 414 thus obtained and the total image degradationamount in FIG. 36A.

(3) A description will be given of a method of FIG. 41C. In FIG. 41C, anadjusted handheld blur amount is obtained by using a waveform(correction change amount) 415 obtained by linearly approximating thereference image degradation waveform 412 obtained in FIG. 41A. Ahandheld blur amount can be stably obtained by using a differencebetween the adjusted image degradation waveform 415 thus obtained andthe total image degradation amount in FIG. 36A. A waveform on whichlinear approximation is based is not limited to the reference imagedegradation waveform 412 in FIG. 41A, but may be, for example, theadjusted image degradation amount 414 in FIG. 41B.

(4) In FIG. 41D, an adjusted reference image degradation amount isobtained by using a straight line (correction change amount) 416obtained by averaging the reference image degradation amounts atrespective exposure times of the reference image degradation waveform412 obtained in FIG. 41A. A handheld blur amount can be stably obtainedby using a difference between the adjusted handheld blur waveform(straight line) 416 thus obtained and the total image degradation amountillustrated in FIG. 36A. A waveform on which the average straight lineis based is not limited to the reference image degradation waveform 412in FIG. 41A, but may be the adjusted image degradation amount 414 inFIG. 41B.

The corrector 377 illustrated in FIG. 37 is a unit configured to adjustand calculate a singular image degradation amount in the above items (1)to (4) and to set the adjusted image degradation amount. As describedabove, according to this embodiment, even if there is disturbance ineither the reference image degradation amount data or the handheld bluramount data, the disturbance can be corrected and camera handheld blurcan be evaluated with high accuracy.

Sixth Embodiment

A description will now be given of a sixth embodiment according to thepresent disclosure. Referring now to FIG. 42 , a description will begiven of an operation of an image evaluating unit 271 according to thisembodiment. FIG. 42 is a block diagram of the image evaluating unit 271.Since FIG. 42 is based on FIGS. 28 and 37 , common portions will bedesignated by the same reference numerals, and a description thereofwill be omitted. In FIG. 42 , reference numeral 421 denotes a detectorconfigured to detect disturbance. The detector 421 includes an internalprocessing unit 424 configured to process data of a handheld blur amountin a case where the handheld blur amount is input. A determination unit425 determines whether or not there is disturbance in the data processedby the processing unit 424. The detector 421 transmits the result of theinternal determination unit 425 to a switching unit 376.

In a case where it is determined that there is no disturbance, thedetermination unit 425 transmits handheld blur amount data 286 to an Aroute, and an evaluation unit 423 performs handheld blur evaluation. Ina case where it is determined that there is disturbance, thedetermination unit 425 transmits the handheld blur amount data 286 to aB route, and after correction processing is performed in the corrector422, the evaluation unit 423 performs handheld blur evaluation.

Referring now to FIGS. 43A and 43B, a description will be given ofoperations of the processing unit 424 and the determination unit 425provided in the detector 421. FIG. 43A is a flowchart illustrating aspecific operation of the processing unit 424. Since FIG. 43A is basedon FIG. 13 , common portions will be designated by the same referencenumerals, and a description thereof will be omitted.

In a case where the handheld blur amount is input to the detector 421,the processing unit 424 starts the operation. In step S431, theprocessing unit 424 calculates the change rate of the input referenceimage degradation amount. In a case where the change rate is less thanthe threshold, the result is recorded as Norm in step S432 and the flowends. The change rate calculating method and the threshold determiningmethod are similar to those described with reference to FIGS. 38A and38B, and a description thereof will be omitted. In a case where it isdetermined that the change rate is higher that the threshold, the resultis recorded as Err in step S433, the exposure time at which the changerate is higher than the threshold is recorded as Tv_Handheld blur, andthe flow ends.

FIG. 43B is a flowchart illustrating the operation of the determinationunit 425 in the detector 421 illustrated in FIG. 42 . Since FIG. 42B isbased on FIG. 13C, the common portions will be designated by the samereference numerals and a description thereof will be omitted. After theoperation of the processing unit 424 ends, the determination unit 425starts the operation based on the result.

In step S434, in a case where the result of the processing unit 424illustrated in FIG. 43A is Norm lower than the threshold, it isdetermined in step S435 that there is no disturbance, and the operationends. In a case where the result of step S434 is NO, it is determined instep S436 that there is disturbance in the handheld blur amount data,and the flow ends. The handheld blur amount data with disturbance ishandheld blur amount data determined to have the disturbance.

In a case where it is determined that there is disturbance due to thedetermination of presence and absence of the disturbance described withreference to FIGS. 43A and 43B, the corrector 422 corrects thedisturbance. Since the correction method is similar to that illustratedin FIGS. 41A, 41B, and 41C, a detailed description thereof will beomitted.

As described above, even if there is disturbance in the handheld bluramount data, this embodiment can correct the disturbance and accuratelyevaluate the handheld blur in the camera.

Seventh Embodiment

A description will be given of a seventh embodiment according to thepresent disclosure. FIG. 44 is a schematic diagram of a handheld blurevaluating apparatus 100 d 1 that executes a camera handheld blur amountmeasuring method according to this embodiment. In FIG. 44 , referencenumeral 11 denotes a measurement camera (imaging unit), which isinstalled on an excitation table (excitation unit) 12. The measurementcamera 11 and the excitation table 12 are controlled through a controlunit (CTRL) 443 of a computer 442. The excitation table 12 excites themeasurement camera 11 about the arrow 12 aP based on the excitationwaveform data 13 stored in a memory 444 in the computer 442. Themeasurement camera 11 faces the chart 14 as an object, and a chart imagecaptured by the measurement camera 11 that is being excited by theexcitation table 12 is input to an image evaluating unit (measurementcamera image evaluating unit (MCIEU)) 446 in the computer 442. The imageevaluating unit 446 detects a width of a boundary between two adjacentcolors in the captured chart image, and measures the deteriorationdegree of the captured image caused by the excitation. The imageevaluating unit 446 evaluates the handheld blur of the measurementcamera from the deterioration degree. Since the details of theevaluation method are similar to those of the prior art, a descriptionthereof will be omitted.

In order to evaluate the handheld blur of the measurement camera 11, ameasurement camera reference image degradation amount to be superimposedon the measurement camera signal in the handheld blur-free state isobtained, and subtracted from the camera signal in the handheld blurstate. Since handheld blur is evaluated by using the exposure time as aparameter, the measurement camera reference image degradation amount isobtained by each exposure time. Here, the exposure time, F-number(aperture value), and ISO speed of the measurement camera 11 are atissue. In addition, a change in a measurement camera reference imagedegradation amount becomes problematic in a measurement environment,such as influence from the outside such as building shakes, anillumination condition such as chart shadows due to lighting, and adistance error between the chart and the measurement camera, and chartwarpage. This is because due to this change, the measurement camerareference image degradation amount in the handheld blur state and themeasurement camera reference image degradation amount in the handheldblur-free state are different, even if they are subtracted, themeasurement camera reference image degradation amount cannot becancelled out, and handheld blur cannot be correctly calculated.Therefore, it is necessary to obtain a stable measurement camerareference image degradation amount regardless of the measurementenvironment.

In FIG. 44 , reference numeral 441 denotes a reference camera (referencedetermination unit), which images the chart 14 with substantially thesame composition as that of the measurement camera 11. The referencecamera 441 is a mass-production product having a known point spreadfunction (PSF), and is selected to have a PSF with stable dispersionamong individuals of the same model and a normal distribution with smallvariance. Cameras of the same model are used as the reference camera ina case where camera handheld blur is evaluated at various locations.Here, a handheld blur amount in a case where the chart 14 has previouslybeen imaged by exposure time by the reference camera 441 is determinedas a specified (or regulated) image degradation amount.

Referring now to FIG. 45 , a description will be given of a chartaccording to this embodiment. FIG. 45 is a plan view of a handheld blurmeasurement chart. The chart 14 is a handheld blur measurement chartdisplayed on a monitor illustrated in FIG. 45 . The handheld blurmeasurement chart is a chart that is used as an object in measuring theimage stabilizing effect. A black area 141 is a low-brightness(lightness or value) area (first color) painted in black. A white area142 is a white high-brightness area (second color). An imaging areamarker 143 is a marker that is used as a guide for setting the imagingarea. The handheld blur measurement chart is not limited to thatillustrated in FIG. 45 , and can use various charts. For example,instead of a combination of black and white as illustrated in FIG. 45 ,a pattern of a plurality of types of color areas having chroma may beused. At this time, a reflectance ratio of a high-brightness color and alow-brightness color may be 4:1 or higher. The handheld blur measurementchart may be a pattern in which an actual image is partiallyincorporated as well as a geometrical pattern. That is, the handheldblur measurement chart may be any chart that includes a plurality ofcolor areas.

This embodiment evaluates a handheld blur amount in an image bymeasuring the handheld blur in the image at a boundary between thedifferent color areas on the handheld blur measurement chart.Conceptually, the color in the color area here includes black, gray, andwhite that do not have chroma, and also includes colors that havechroma. The image degradation refers to a phenomenon in which thesharpness of a captured image is reduced due to misalignment between afocal plane of a lens and an imaging plane of an image sensor, camerahandheld blur, or the like. The image degradation can also occur due toimage processing of image data. An image degradation amount isquantified image degradation magnitude. A boundary width between theblack area 141 and the white area 142 on the chart 14 can be adjusted byan image adjusting unit (changing unit) 447. In a case where there are aplurality of reference image degradation amount confirmation points, theimage adjusting unit 447 can adjust the boundary width at an arbitrarylocation on the chart.

The reference camera 441 obtains the imaging result by exposure time,and compares the reference camera reference image degradation amountobtained by a reference camera image evaluating unit (RCIEU) (imagedegradation amount calculator) 448 with a predetermined specified imagedegradation amount through the detector 449. The image adjusting unit447 controls the boundary width on the chart 14 based on the result.Therefore, the measurement camera reference image degradation amount ofthe measurement camera 11 can be stably obtained regardless of themeasurement environment.

Referring now to FIG. 46 , a description will be given of an imagedegradation amount. FIG. 46 is a graph illustrating changes in thenormalized level value at the boundary between the black area and thewhite area in the image on the chart 14 captured by the camera. Ahorizontal axis represents the number of pixels in the image sensor inthe camera, and a vertical axis represents a level value of thenormalized image signal (here normalized luminance). A level value ofthe image signal in the black area is set to 0 and a level value of theimage signal in the white area is set to 255 by normalization. In FIG.46 , the handheld blur amount of the image is a boundary portion betweena white area P1 and a black area P2 illustrated in A, and is a distancebetween level values changing from 0 to 255 in the normalized imagesignal. The details of the handheld blur amount calculating method aredisclosed in prior art, and thus a description thereof will be omittedhere.

Referring now to FIGS. 47A and 47B, a description will be given of ahandheld blur evaluating method of the measurement camera. FIGS. 47A and47B illustrate a simple flowchart of the handheld blur evaluating methodof the measurement camera in a case where imaging of the referencecamera and imaging of the measurement camera are performed at the sametime.

First, in step S471, the exposure times of the measurement camera 11 andthe reference camera 441 are set. For example, in a case where the focallength of the imaging lens in the measurement camera 11 is 100 mm andthe size of the image sensor is a full-size format (36 mm in width and24 mm in height), the exposure time is initially set to 1/100 seconds.

Next, in step S472, the chart 14 is imaged by the reference camera 441,and the reference camera reference image degradation amount is obtainedby the reference camera image evaluating unit 448. The reference camerareference image degradation amount is acquired by obtaining the imagedegradation amount from the boundary width between the black area andthe white area in the image on the chart 14 captured by the referencecamera in the stationary state as described above.

Next, in step S473, the control unit 443 determines whether or not aratio of a specified image degradation amount of the reference camera441 to a reference camera reference image degradation amount obtained instep S472 (referred to as an image degradation amount ratio hereinafter)is 1. In a case where the image degradation amount ratio is 1, thespecified image degradation amount of the reference camera 441 and thereference image degradation amount coincide with each other, and thisstate is an ideal state. However, the handheld blur amount ratio of 1may have a range, and the determination may be made so that the ratiocan fall within that range (for example, the error is ±5%). In a casewhere there are a plurality of confirmation locations of the referencecamera reference image degradation amount, the image degradation amountratio is confirmed at all locations. In a case where the imagedegradation amount ratio at all locations is 1 or falls within the setrange, the flow proceeds to step S475. Otherwise, the flow proceeds tostep S474.

In step S474, the boundary width between the black area 141 and thewhite area 142 of the chart 14 is adjusted based on the imagedegradation amount ratio obtained in step S473. For example, in a casewhere the reference camera reference image degradation amount obtainedin step S473 is larger than the specified image degradation amount by10%, the boundary width of the chart 14 is narrowed according to thatamount. Conversely, in a case where the handheld blur amount is smallerthan the specified image degradation amount by 10%, the boundary widthof the chart 14 is widened according to that amount. By repeating stepsS472 to S474, the reference camera reference image degradation amount ismade closer to the specified image degradation amount.

Referring now to FIGS. 48A and 48B, a description will be given of arelationship between the image degradation amount of the referencecamera 441 and the boundary width of the chart 14. FIG. 48A is a graphillustrating changes in a normalized level value at the boundary betweenthe black area and the white area in the image on the chart 14, whereB_(I), C_(I), and P_(I) respectively represent boundary widths. FIG. 48Bis a graph illustrating how the normalized level value changes at theboundary between the black area and the white area in the captured imageon the chart 14 captured by the reference camera 441. P_(O) is aboundary width of the specified image degradation amount. Each of B_(O)and C_(O) represents a boundary width of a reference image degradationamount. The boundary widths B_(O), C_(O), and P_(O) in FIG. 48Bcorrespond to the results of multiplying the boundary widths B_(I),C_(I), and P_(I) in FIG. 48A by the PSF, which will be described below.In both FIGS. 48A and 48B, a horizontal axis represents the number ofpixels in the image sensor in the camera, and a vertical axis representsa level value of the normalized image signal.

Since the PSF can be regarded as a transfer function between an image tobe captured and a captured image, the following relationship isestablished where O is a captured image by the reference camera 441 andI is an image of the chart 14:

O=I⊗PSF  (1)

Since this embodiment divides the PSF into PSF1 of the camera itself andPSF2 that represents an image influence factor such as a measurementenvironment, equation (1) can be expressed as follows.

O=I⊗PSF1⊗PSF2  (2)

PSF1 of the camera itself represents the resolving power of the camera,is a function that expresses the influence of a shift between the focalplane of the lens and the imaging plane of the image sensor in thecamera, image processing in the camera, and lens aberration, andcorresponds to a known image acquiring state. PSF1 cannot be arbitrarilycontrolled by a measuring person (measurer), but can be previouslyrecognized. Therefore, in selecting the reference camera 441, selectingPSF1 that has a normal distribution and small variance can reduce theinfluence of the camera itself on the captured image.

PSF2, which represents an image influence factor such as the measurementenvironment, is a function that expresses the influence on an image dueto disturbance such as building shakes, lighting, a distance errorbetween the chart and the measurement camera, and chart warping, andchanges depending on the measurement environment. Therefore, it isdifficult to previously recognize it, and the measuring person cannotarbitrarily control it. PSF2 corresponds to an unknown image acquiringstate. Thus, the captured image O is an image obtained by applying aknown image acquiring state and an unknown image acquiring state to thechart.

Image I in the chart 14 is an image captured by reference camera 441,and is the only image arbitrarily controllable by the measuring personin equation (2). Therefore, the captured image O by the reference camera441 in equation (2) is affected by PSF1 of the camera itself, whichcannot be controlled by the measuring person, and PSF2 representing animage influence factor such as the measurement environment, but can bearbitrarily controlled by controlling the image I of the chart 14. In acase where it is illustrated in FIGS. 48A and 48B and the boundary widthof the reference image degradation amount is larger than the boundarywidth P_(O) of the specified image degradation amount, like C_(O), theboundary width on the image I side of the chart 14 may be narrowed fromC_(I) to P_(I). In a case where the boundary width of the referenceimage degradation amount is narrower than the boundary width P_(O) ofthe specified image degradation amount as in B_(O), the boundary widthon the image I side of the chart 14 may be narrowed from B_(I) to P_(I).From the above, this embodiment makes constant the image degradationamount obtained from the image O captured by the reference camera 441 bycontrolling the image I of the chart 14, that is, the boundary width,cancels out the influence of the measurement environment on the image,and provides an always stable image degradation amount.

In step S475 in FIG. 47A, the chart 14 is imaged by the measurementcamera 11, and the measurement camera reference image degradation amountis obtained by the image evaluating unit 446. Next, in step S476, themeasurement camera reference image degradation amount obtained in stepS475 is recorded in a storage unit 445 by exposure time (first 1/100seconds in this example).

Steps S477 to S479 are similar to steps S472 to S474. Here, it isconfirmed whether or not the reference camera reference imagedegradation amount shifts from the specified image degradation amount inmeasuring the measurement camera reference image degradation amount insteps S475 and S476, and the boundary width of the chart 14 is adjusted,as necessary.

In step S4710, it is determined whether measurement of the measurementcamera reference image degradation amount has been completed. In a casewhere the measurement camera reference image degradation amount hasalready been recorded in step S476, the flow proceeds to step S4711. Onthe other hand, in a case where the measurement camera reference imagedegradation amount has not yet been recorded, the flow returns to stepS477.

In step S4711, the flow returns to step s471 until the exposure timemeasured by the measurement camera 11 is completed. In a case where themeasurement for all exposure times is completed, the flow proceeds tostep S4712. In step S4712, the measurement camera 11 is excited bydriving the excitation table 12 with the excitation waveform data 13.Next, in step S4713, the exposure time of the measurement camera 11 isset as in step S471.

Next, in step S4714, the measurement camera 11 images the chart 14, andthe image evaluating unit 446 obtains the total image degradationamount. Here, the total image degradation amount is a handheld bluramount that occurs in a captured image in a case where the camera isexcited. Next, in step S4715, the obtained total image degradationamount is recorded in the storage unit 445 by exposure time (in thisexample, 1/100 seconds for the first time). Next, in step S4716, thecontrol unit 443 determines whether or not the specified number ofimages have been completely captured in the same exposure time. Forexample, 100 images are to be captured, the flow returns to S4714 untilall 100 images are captured, and after all of 100 images are completelycaptured, the flow proceeds to step S4721.

Steps S4717 to S4719 are similar to steps S472 to S474. Here, it isconfirmed whether or not the reference camera reference imagedegradation amount shifts from the specified image degradation amount inmeasuring the measurement camera total image degradation amount in stepsS4714 to S4716, and the boundary width of the chart 14 is adjusted, ifnecessary.

In step S4720, the control unit 443 determines whether or not themeasurement of the measurement camera total image degradation amount iscompleted. In a case where the specified number of images in step S4716has been completely captured, the flow proceeds to step s4721. On theother hand, in a case where the specified number of images has not beencompletely captured, the flow returns to step S4717.

In step S4721, the flow returns to step S4713 until the exposure timemeasured by the measurement camera 11 ends. In a case where themeasurement for all exposure times is completed, the flow ends throughstep S4721. In evaluating camera handheld blur, a value obtained bysubtracting the measurement camera reference image degradation amount byexposure time recorded in step S476 from the average total imagedegradation amount for each exposure time recorded in step S4715 is setas a measurement camera handheld blur amount.

Referring now to FIG. 49 , a description will be given of an example inwhich the chart 14 is replaced with a paper chart 114 instead of amonitor. FIG. 49 is a schematic diagram of a handheld blur evaluatingapparatus 100 d 2 in a case where the chart 114 is a paper chart.

A plurality of paper charts 114 a to 114 n are prepared, and theboundary width of each chart is increased in order. Any one of the papercharts 114 a to 114 n is attached to an unillustrated adsorption panelfacing the measurement camera 11 and the reference camera 441. Thereference camera reference image degradation amount is output to theimage selecting unit (changing unit) 4410. The image selecting unit 4410changes the boundary width of the chart by displaying a proper chartbased on an image degradation amount ratio between the input referencecamera reference image degradation amount and the specified imagedegradation amount. For example, in a case where the reference camerareference image degradation amount is larger than the specified imagedegradation amount by 10%, a chart number with a boundary width narrowerthan that of the chart currently in use is displayed according to themagnitude. Conversely, in a case where the reference camera referenceimage degradation amount is smaller than the specified image degradationamount by 10%, a chart number with a wider boundary width is displayedaccording to the magnitude. The measuring person selects one of thepaper charts 114 a to 114 n according to the display, attaches it to theabsorption panel, and confirms the reference camera reference imagedegradation amount again. In a case where there are a plurality ofreference image degradation amount confirmation locations, the chartswith partially different boundary widths are exchanged so that thereference camera reference image degradation amount coincides with thespecified image degradation amount at all confirmation locations. Thus,the measurement camera reference image degradation amount, which changesdue to the influence of the measurement environment, can be alwaysstabilized by feeding it back to the chart 14 using the reference camerareference image degradation amount, and the camera handheld blur can beevaluated with higher accuracy.

Eighth Embodiment

A description will be given of an eighth embodiment according to thedisclosure. The seventh embodiment stabilizes the measurement camerareference image degradation amount by feeding back the imaging result ofthe reference camera 441 to the chart 14 simultaneously with thereference image degradation amount measurement by the measurement camera11. On the other hand, this embodiment separately performs the imagingby the reference camera 441 and the reference image degradation amountmeasurement by the measurement camera 11, feeds back the imaging resultof the reference camera 441 to the chart 14, and then makes themeasurement camera 11 perform the measurement, thereby stabilizing themeasurement camera reference image degradation amount.

Referring now to FIGS. 50A and 50B, a description will be given of aconfiguration of a handheld blur evaluating method of the cameraaccording to this embodiment. Since the configuration according to thisembodiment is obtained by simply separating the measurement camera 11and the reference camera 441 in the seventh embodiment into two, adetailed description of each block will be omitted.

FIG. 50A is a schematic diagram of a handheld blur evaluating apparatus100 e in measuring the reference camera reference image degradationamount with the reference camera 441 and adjusting the boundary width ofthe chart 14. The reference camera 441 is installed at a position facingthe chart 14, and each component in the reference camera 441 andcomputer 442 is controlled by the control unit 443.

FIG. 50B is a schematic diagram of a handheld blur evaluating apparatus100 f in a case where the measurement camera 11 measures the measurementcamera reference image degradation amount. The measurement camera 11 isinstalled at a position where the reference camera 441 measured thechart 14, and each component in the measurement camera 11 and thecomputer 442, and the excitation table 12 are controlled by the controlunit 443.

Referring now to FIGS. 51A and 51B, a description will be given of thehandheld blur evaluating method of the measurement camera 11. FIGS. 51Aand 51B illustrate a simple flowchart of the handheld blur evaluatingmethod of the measurement camera 11 in a case where imaging of thereference camera and imaging of the measurement camera are separatelypreformed. A description of the same block as that in the flow of FIGS.47A and 47B will be omitted.

First, in step S511, the reference camera 441 is disposed at a positionfacing the chart 14. At this time, an imaging distance of the referencecamera 441 is set such that a range within an imaging area marker of thechart 14 appears almost entirely on the screen. After the referencecamera 441 can be installed at the position facing the chart 14, theflow proceeds to step S471.

In step S512, the measurement camera 11 is installed at the positionfacing the chart 14. At this time, an imaging distance of themeasurement camera 11 is set such that a range within the imaging areamarker of the chart 14 appears almost entirely on the screen, similarlyto the reference camera 441 in step S511. After the measurement camera11 is installed at the position facing the chart 14, the flow proceedsto step S471.

Thus, this embodiment can stabilize the measurement camera referenceimage degradation amount, which changes due to the influence of themeasurement environment, etc., by feeding it back to the chart 14 usingthe reference camera reference image degradation amount, and evaluatecamera handheld blur with higher accuracy.

Ninth Embodiment

A description will be given of a ninth embodiment according to thepresent disclosure. FIG. 52 is a schematic diagram of a handheld blurevaluating apparatus 100 g according to this embodiment. As illustratedin FIG. 52 , this embodiment performs measurement with the measurementcamera 11 by setting a state similar to that of the fourth embodiment.That is, the measurement camera 11 is installed on the excitation table(excitation unit) 12. The excitation table 12 excites the measurementcamera 11 about the arrow 12 aP based on the excitation waveform data13. The excitation table 12 can be switched between an excitation stateand a stationary state by control. The measurement camera 11 faces thechart 14 as an object, and a chart image captured by the measurementcamera 11 that is being excited by the excitation table is input to aresolution calculator 500. The chart image can be acquired while theluminance of the object (imaging environment) is changed by illumination14 k. The chart to be imaged at this time can use that illustrated inFIG. 32 of the fourth embodiment. Another chart that can be used tomeasure so-called resolution may also be used.

In this embodiment, the resolution may be defined based on a luminancechange width. More specifically, in a case where a luminance changewidth 332 in FIGS. 33A, 33B, 33C, and 33D is narrow, the resolution isconsidered to be high, and in a case where the luminance change width332 is wide, the resolution is considered to be low. The resolutioncalculator 500 obtains the resolution from the imaging magnification atthe time of imaging, chart information, the luminance change width 332described above, and the like.

In the description of this embodiment, the output of the resolutioncalculator 500 is expressed using the term “resolution” as describedabove. As apparent from the measuring method of FIG. 52 , a factor thatgoverns the resolution is so-called image handheld blur, so it may beassumed that high resolution means less handheld blur, and lowresolution means more handheld blur. That is, a vertical axis in FIGS.53A to 56B, which will be described below, represents the resolution,but it may be considered to be a handheld blur amount (although asmaller handheld blur amount is located high). Also, in FIGS. 53A to56B, a horizontal axis represents the luminance of the object, but itmay be considered to be exposure time. In FIG. 52 , an image is acquiredwhile the luminance of the object is changed using the illumination 14k, and at this time, the darker the luminance is, the longer theexposure time is. That is, the luminance and exposure time areassociated with each other. In a case where it is bright, the exposuretime is short, and in a case where it is dark, the exposure time islong. Although the horizontal axis in FIGS. 53A to 56B, which will bedescribed below, represents luminance, it may be considered to beexposure time (a longer exposure time is located rightward). Actually,FIGS. 57A, 57B, 57C, and 57D illustrate an example in which a horizontalaxis represents exposure time. The handheld blur evaluating methoddescribed below may be performed using each of a relationship betweenthe luminance and the resolving power and a relationship between theexposure time and the resolving power, and may again perform theevaluation in a case where a difference between their values is higherthan a threshold, or may perform final handheld blur evaluation usingboth results.

FIGS. 53A to 56B explain the handheld blur evaluating methodillustrating a relationship between the luminance and the resolution. Inthe graphs illustrated in FIGS. 53A to 56B, a horizontal axis representsthe luminance, and a vertical axis represents the resolution. Asillustrated in FIG. 52 , the measurement camera 11 is installed in theexcitation table 12, and a result of an image processed by theresolution calculator 500 is graphed while the luminance is changed bythe illumination 14 k. The horizontal axes of FIGS. 53A to 56B becomedarker as the position moves to the right. In a case where it becomesdark, the resolution drops due to the influence of the handheld blur.Therefore, the graph becomes a decreasing graph.

In FIGS. 53A to 56B, each of FIGS. 53A, 54A, 55A, and 56A illustratesthe result of the measurement camera 11 determined to have highperformance in the handheld blur evaluation, and each of FIGS. 53B, 54B,55B, and 56B illustrates the result of the measurement camera 11determined to have low performance in the handheld blur evaluation. Thefollowing description illustrates some handheld blur evaluating methodsbased on a relationship between luminance or exposure time andresolution.

Referring to FIGS. 53A and 53B, a description will be given of a methodof evaluating image stabilizing performance by linearly approximatingthe resolution of a constant luminance range (or a constant exposuretime range) by the resolution calculator (slope calculator and imagestabilization evaluating unit) 500. In FIGS. 53A and 53B, referencenumerals 501 a and 501 b denote resolutions, and reference numerals 511a and 511 b denote straight lines linearly approximating theresolutions. Assume that data is measured at seven points indicated byblack dots in a luminance range illustrated in FIGS. 53A and 53B. A andB represent slopes of the straight lines 511 a and 511 b obtained bylinearly approximating this range, respectively. As apparent from FIGS.53A and 53B, the slope A in FIG. 53A, which is determined to have highperformance in the handheld blur evaluation, is smaller than the slope Bin FIG. 53B, which is determined to have low performance in the handheldblur evaluation. In other words, the smaller the slope is, the betterthe performance is.

Referring now to FIGS. 54A and 54B, a description will be given of amethod in which the resolution calculator (slope calculator and imagestabilization evaluating unit) 500 obtains a slope of a straight lineconnecting two resolutions with different luminances (or exposure times)and evaluates the image stabilizing performance. Those elements in FIGS.54A and 54B, which are corresponding elements in FIGS. 53A and 53B, willbe designated by the same reference numerals. In FIGS. 54A and 54B,reference numerals 504 a and 504 b denote predetermined luminancesdefining straight lines, and reference numerals 505 a and 505 b denoteother luminances different from the luminances 504 a and 504 b definingstraight lines. Reference numeral 508 a denotes a straight line passingthrough the resolutions corresponding to the luminances 504 a and 505 a,and reference numeral 508 b denotes a straight line passing through theresolutions corresponding to the luminances 504 b and 505 b. A and Brepresent slopes of the straight lines 508 a and 508 b, respectively. Asapparent from FIGS. 54A and 54B, the slope A in FIG. 54A, which isdetermined to have high performance in the handheld blur evaluation, issmaller than the slope B in FIG. 54B, which is determined to have lowperformance in the handheld blur evaluation. That is, the smaller theslope is, the better the performance is.

Referring now to FIGS. 55A and 55B, a description will be given of amethod of evaluating the image stabilizing performance from anintersection between resolution with given luminance (or exposure time)and a straight line obtained in a constant luminance range. Thoseelements in FIGS. 55A and 55B, which are corresponding elements in FIGS.53A, 53B, 54A, and 54B, will be designated by the same referencenumerals. In FIGS. 55A and 55B, reference numerals 506 a, 507 a, 506 b,and 507 b denote predetermined luminances that are used to calculate aslope. Reference numeral 521 a denotes a straight line passing throughthe resolutions 506 a and 507 a, and reference numeral 521 b denotes astraight line passing through the resolutions 506 b and 507 b. Referencenumerals 522 a and 522 b denote resolutions corresponding to theluminances 504 a and 504 b, and reference numeral 523 a denotesluminance corresponding to an intersection between the straight lines521 a and 522 a, and reference numeral 523 b denotes luminancecorresponding to an intersection between the straight lines 521 b and522 b. A is synonymous with 523 a and B is synonymous with 523 b. Asapparent from FIGS. 55A and 55B, the luminance A in FIG. 55A, which isdetermined to have high performance in the handheld blur evaluation, islocated at a position darker than that of (on the right side in FIGS.55A and 55B of) the luminance B in FIG. 55B, which is determined to havelow performance in the handheld blur evaluation. That is, it isdetermined that the performance with darker (lower) luminancecorresponding to this intersection is better.

Referring now to FIGS. 56A and 56B, a description will be given of amethod of evaluating image stabilizing performance based on anintersection between straight lines obtained in two different ranges.Those elements in FIGS. 56A and 56B, which are corresponding elements inFIGS. 53A to 55B, will be designated by the same reference numerals.Similarly to FIGS. 54A and 54B, reference numeral 508 a denotes astraight line passing through the resolutions corresponding to theluminances 504 a and 505 a, and reference numeral 508 b denotes astraight line passing through the resolutions corresponding to theluminances 504 b and 505 b. Similarly to FIGS. 55A and 55B, referencenumeral 521 a denotes a straight line passing through the resolutions506 a and 507 a, and reference numeral 521 b denotes a straight linepassing through the resolutions 506 b and 507 b. Reference numeral 531 adenotes luminance corresponding to the straight lines 508 a and 521 a,and reference numeral 531 b denotes the luminance corresponding to thestraight lines 508 b and 521 b. A is synonymous with 531 a and B issynonymous with 531 b. As apparent from FIGS. 56A and 56B, the luminanceA in FIG. 56A, which is determined to have high performance in thehandheld blur evaluation, is located at a position darker than that of(on the right side in FIGS. 56A and 56B of) the luminance B in FIG. 56B,which is determined to have low performance in the handheld blurevaluation. That is, it is determined that the performance with darker(lower) luminance corresponding to this intersection is better.

In the examples of FIGS. 53A to 56B, handheld blur evaluation isperformed using predetermined luminances 504, 505, 506, and 507. Anothermethod for determining a data range to be referred to by the slopecalculator will be described with reference to FIGS. 57A, 57B, 57C, and57D.

In FIGS. 57A, 57B, 57C, and 57D, a horizontal axis represents exposuretime and a vertical axis represents resolution. Those elements in FIGS.57A, 57B, 57C, and 57D, which are corresponding elements in FIGS. 53A to56B, will be designated by the same reference numerals. In FIGS. 57A,57B, 57C, and 57D, f written as 1/f is a converted focal length of animaging lens for the measurement camera 11 (a converted focal length forthe 35 mm version). The exposure time of 1/f is exposure time at whichhandheld blur becomes noticeable in a case where a camera isconventionally hand-held. That is, in a case where the converted focallength (f) is 100 mm, 1/f is 1/100 [s] of the exposure time. Referencenumeral 554 denotes exposure time that is not affected by handheld blur,and reference numeral 555 denotes exposure time of 1/f. Other symbolswill be described in the description of each figure.

Referring now to FIG. 57A, a description will be given of a method ofdetermining data or a data range to be referred to, based on 1/f. InFIG. 57A, the exposure time of 1/f is set to a first reference(=exposure time 555). Next, a point where the exposure time is longer byan amount indicated by an arrow 560 is set to a second reference(=exposure time 561). The length of the arrow 560 may be previouslydetermined. For example, the exposure time may become longer 16-fold (=4steps). A straight line is determined using these two points or a datarange sandwiched between these two points. In FIG. 57A, referencenumeral 562 denotes a straight line passing through these two points.

Referring now to FIG. 57B, a description will be given of a method ofdetermining data or a data range to be referred to by using resolutiondrop. In FIG. 57B, first, resolution 570 of the exposure time 554 whichis sufficiently bright and is not affected by handheld blur is obtained.From this, resolution 572 that is lower by a specified amount 571 isobtained. The specified amount 571 may be set to a value suitable formeasurement. In a case where the amount is too small, the measurementbecomes unstable, and in a case where the amount is too large, theevaluation is made in a range in which handheld blur influence is toolarge. Exposure time 573 at which the resolution 572 and the measurementdata 501 intersect each other is set as a first reference. Next, a pointwhere the exposure time is longer by an amount indicated by an arrow 574is set as a second reference (=exposure time 561). The length of thearrow 574 may be previously determined. For example, the exposure timemay become longer quadruple (=two stages). A straight line may bedetermined by using these two points or a data range sandwiched betweenthe two points. In FIG. 57B, reference numeral 576 denotes a straightline passing through the two points.

Referring now to FIG. 57C, a description will be given of a method ofdetermining data or a data range to be referred to by using resolutiondrop similarly to FIG. 57B. In FIG. 57C, permissible resolution 580 ispreviously determined. Exposure time 581 at which the resolution 580intersects the measurement data 501 is set as a first reference. Next, apoint where the exposure time is longer by an amount indicated by anarrow 582 is set as a second reference (=exposure time 583). The lengthof the arrow 582 may be previously determined. For example, the exposuretime may be longer quadrupled (=two stages). A straight line isdetermined using these two points or a data range sandwiched between thetwo points. In FIG. 57C, reference numeral 584 denotes a straight linepassing through the two points.

Referring now to FIG. 57D, a description will be given of a method ofdetermining data or a data range to be referred to by using theperformance without image stabilization. Reference numeral 590 in FIG.57D denotes resolution 591 at the exposure time 555 (1/f) in a casewhere the image stabilizing function of the measurement camera 11 isturned off. Exposure time 592 at which the resolution 591 and themeasurement data 501 intersect each other is set as a first reference.Next, a point where the exposure time is longer by an amount indicatedby an arrow 593 is set as a second reference (=exposure time 594). Thelength of the arrow 593 may be previously determined. For example, theexposure time may be longer quadrupled (=two stages). A straight line isdetermined using these two points or a data range sandwiched between thetwo points. In FIG. 57D, reference numeral 595 denotes a straight linepassing through the two points.

Other Embodiments

Embodiment(s) of the disclosure can also be realized by a computer of asystem or apparatus that reads out and executes computer-executableinstructions (e.g., one or more programs) recorded on a storage medium(which may also be referred to more fully as a ‘non-transitorycomputer-readable storage medium’) to perform the functions of one ormore of the above-described embodiment(s) and/or that includes one ormore circuits (e.g., application specific integrated circuit (ASIC)) forperforming the functions of one or more of the above-describedembodiment(s), and by a method performed by the computer of the systemor apparatus by, for example, reading out and executing thecomputer-executable instructions from the storage medium to perform thefunctions of one or more of the above-described embodiment(s) and/orcontrolling the one or more circuits to perform the functions of one ormore of the above-described embodiment(s). The computer may comprise oneor more processors (e.g., central processing unit (CPU), microprocessing unit (MPU)) and may include a network of separate computersor separate processors to read out and execute the computer-executableinstructions. The computer-executable instructions may be provided tothe computer, for example, from a network or the storage medium. Thestorage medium may include, for example, one or more of a hard disk, arandom-access memory (RAM), a read-only memory (ROM), a storage ofdistributed computing systems, an optical disc (such as a compact disc(CD), digital versatile disc (DVD), or Handheld bluray Disc (BD)™), aflash memory device, a memory card, and the like.

While the disclosure has been described with reference to embodiments,it is to be understood that the disclosure is not limited to thedisclosed embodiments. The scope of the following claims is to beaccorded the broadest interpretation so as to encompass all suchmodifications and equivalent structures and functions.

Each embodiment can provide a handheld blur evaluating apparatus, ahandheld blur evaluating method, and a storage medium, each of which canhighly accurately evaluate the handheld blur in an imaging unit. Eachembodiment can provide a method for manufacturing an imaging unit thatcan provide highly accurate image stabilization.

What is claimed is:
 1. A handheld blur evaluating apparatus configuredto evaluate a handheld blur of an imaging unit, the handheld blurevaluating apparatus comprising: an excitation unit configured to excitethe imaging unit configured to image an object; a detector configured todetect disturbance in a change amount in measurement data of an imageimaged by changing an imaging condition relating to exposure time orluminance, and a driving state indicating that the excitation unit is ina stationary state or in an excitation state; and a corrector configuredto correct the disturbance.
 2. The handheld blur evaluating apparatusaccording to claim 1, wherein the detector detects the disturbance in acase where a change rate of the change amount calculated for eachimaging condition is equal to or larger than a threshold.
 3. Thehandheld blur evaluating apparatus according to claim 1, wherein thechange amount includes: a stationary-state change amount calculated fromthe measurement data measured in a case where the driving stateindicates the stationary state, and an excitation-state change amountcalculated from the measurement data measured in a case where thedriving state indicates the excitation state.
 4. The handheld blurevaluating apparatus according to claim 2, wherein among first datadetermined by the detector to have the disturbance and second datadetermined by the detector not to have the disturbance, the correctorcorrects the first data.
 5. The handheld blur evaluating apparatusaccording to claim 3, wherein the change amount is handheld blur amountdata calculated by comparing the stationary-state change amount and theexcitation-state change amount.
 6. The handheld blur evaluatingapparatus according to claim 5, wherein the corrector corrects thehandheld blur amount data in which the disturbance is detected by thedetector.
 7. The handheld blur evaluating apparatus according to claim1, wherein the corrector obtains a correction change amount by averagingratios of adjacent change amounts for each different imaging conditionin continuously changed imaging conditions.
 8. The handheld blurevaluating apparatus according to claim 1, wherein the correctorcalculate a specific imaging condition that generates a singular changeamount based on a ratio of adjacent change amounts in continuouslychanged imaging conditions, and replaces the singular change amount in acalculated imaging condition with a correction change amount obtainedusing the adjacent change amounts.
 9. The handheld blur evaluatingapparatus according to claim 8, wherein the corrector calculates thecorrection change amount by linearly approximating the change amount foreach imaging condition or the correction change amount.
 10. The handheldblur evaluating apparatus according to claim 8, wherein the correctorcalculates the correction amount change by averaging the change amountfor each imaging condition or the correction amount change.
 11. Thehandheld blur evaluating apparatus according to claim 1, wherein theobject is a chart, and wherein measurement is made using a measurementcamera as the imaging unit and a width of a boundary determined based onan image obtained as a result of that a reference camera images thechart.
 12. The handheld blur evaluating apparatus according to claim 11,wherein the boundary changes from a first color to a second color, andwherein the chart is configured to change a distance from the firstcolor to the second color.
 13. The handheld blur evaluating apparatusaccording to claim 11, further comprising: an image degradation amountcalculator configured to calculate an image degradation amount from animage obtained from the reference camera; a detector configured todetect the width of the boundary in a case where the image degradationamount of the reference camera becomes a predetermined value; and achanging unit configured to change the width of the boundary of thechart based on a detection result by the detector, and whereinmeasurement using the measurement camera is made using the chart changedby the changing unit.
 14. The handheld blur evaluating apparatusaccording to claim 11, wherein the reference camera and measurementcamera simultaneously image the chart.
 15. The handheld blur evaluatingapparatus according to claim 11, wherein the reference camera andmeasurement camera image the chart at different timings.
 16. Thehandheld blur evaluating apparatus according to claim 11, wherein thechart is configured to change the width of the boundary at an arbitrarylocation on the chart.
 17. A handheld blur evaluating apparatusconfigured to evaluate a handheld blur of an imaging unit configured toimage an object, the handheld blur evaluating apparatus comprising: amemory storing instructions; and a processor configured to execute theinstructions to: calculate a plurality of image degradation amounts or aplurality of resolutions from images imaged by changing luminance usingthe imaging unit; calculate a slope of an image degradation amount orresolution relative to a change in at least one of the luminance andexposure time; and evaluate image stabilizing performance based on theslope.
 18. The handheld blur evaluating apparatus according to claim 17,wherein the processor is configured to obtain a slope of a straight lineobtained by linearly approximating the plurality of image degradationamounts or the plurality of resolutions at a constant luminance orexposure time range.
 19. The handheld blur evaluating apparatusaccording to claim 17, wherein the processor is configured to obtain aslope of a straight line connecting two image degradation amounts orresolutions at different luminances or exposure times.
 20. The handheldblur evaluating apparatus according to claim 17, wherein the processoris configured to evaluate the image stabilizing performance based on theplurality of image degradation amounts or the plurality of resolutionsand the slope at a predetermined luminance or exposure time.
 21. Ahandheld blur evaluating method configured to evaluate a handheld blurof an imaging unit, the handheld blur evaluating method comprising thesteps of: imaging an object using the imaging unit, exciting the imagingunit, detecting disturbance in a change amount in measurement data of animage imaged by changing an imaging condition relating to exposure timeor luminance, and a driving state indicating that the imaging unit is ina stationary state or in an excitation state, and correcting thedisturbance.
 22. A non-transitory computer-readable storage mediumstoring a program that causes a computer to execute the handheld blurevaluating method according to claim 21.